diff --git a/bin/sass.dart b/bin/sass.dart
index 986ff9bcb..ad23649d4 100644
--- a/bin/sass.dart
+++ b/bin/sass.dart
@@ -8,17 +8,14 @@ import 'package:path/path.dart' as p;
 import 'package:stack_trace/stack_trace.dart';
 import 'package:term_glyph/term_glyph.dart' as term_glyph;
 
-import 'package:sass/src/exception.dart';
-import 'package:sass/src/executable/compile_stylesheet.dart';
+import 'package:sass/src/executable/concurrent.dart';
 import 'package:sass/src/executable/options.dart';
 import 'package:sass/src/executable/repl.dart';
 import 'package:sass/src/executable/watch.dart';
 import 'package:sass/src/import_cache.dart';
 import 'package:sass/src/io.dart';
-import 'package:sass/src/io.dart' as io;
 import 'package:sass/src/logger/deprecation_handling.dart';
 import 'package:sass/src/stylesheet_graph.dart';
-import 'package:sass/src/util/map.dart';
 import 'package:sass/src/utils.dart';
 import 'package:sass/src/embedded/executable.dart'
     // Never load the embedded protocol when compiling to JS.
@@ -26,27 +23,6 @@ import 'package:sass/src/embedded/executable.dart'
     as embedded;
 
 Future<void> main(List<String> args) async {
-  var printedError = false;
-
-  // Prints [error] to stderr, along with a preceding newline if anything else
-  // has been printed to stderr.
-  //
-  // If [trace] is passed, its terse representation is printed after the error.
-  void printError(String error, StackTrace? stackTrace) {
-    var buffer = StringBuffer();
-    if (printedError) buffer.writeln();
-    printedError = true;
-    buffer.write(error);
-
-    if (stackTrace != null) {
-      buffer.writeln();
-      buffer.writeln();
-      buffer.write(Trace.from(stackTrace).terse.toString().trimRight());
-    }
-
-    io.printError(buffer);
-  }
-
   if (args case ['--embedded', ...var rest]) {
     embedded.main(rest);
     return;
@@ -84,37 +60,8 @@ Future<void> main(List<String> args) async {
       return;
     }
 
-    for (var (source, destination) in options.sourcesToDestinations.pairs) {
-      try {
-        await compileStylesheet(options, graph, source, destination,
-            ifModified: options.update);
-      } on SassException catch (error, stackTrace) {
-        if (destination != null && !options.emitErrorCss) {
-          _tryDelete(destination);
-        }
-
-        printError(error.toString(color: options.color),
-            options.trace ? getTrace(error) ?? stackTrace : null);
-
-        // Exit code 65 indicates invalid data per
-        // https://www.freebsd.org/cgi/man.cgi?query=sysexits.
-        //
-        // We let exitCode 66 take precedence for deterministic behavior.
-        if (exitCode != 66) exitCode = 65;
-        if (options.stopOnError) return;
-      } on FileSystemException catch (error, stackTrace) {
-        var path = error.path;
-        printError(
-            path == null
-                ? error.message
-                : "Error reading ${p.relative(path)}: ${error.message}.",
-            options.trace ? getTrace(error) ?? stackTrace : null);
-
-        // Error 66 indicates no input.
-        exitCode = 66;
-        if (options.stopOnError) return;
-      }
-    }
+    await compileStylesheets(options, graph, options.sourcesToDestinations,
+        ifModified: options.update);
   } on UsageException catch (error) {
     print("${error.message}\n");
     print("Usage: sass <input.scss> [output.css]\n"
@@ -128,8 +75,11 @@ Future<void> main(List<String> args) async {
     if (options?.color ?? false) buffer.write('\u001b[0m');
     buffer.writeln();
     buffer.writeln(error);
-
-    printError(buffer.toString(), getTrace(error) ?? stackTrace);
+    buffer.writeln();
+    buffer.writeln();
+    buffer.write(
+        Trace.from(getTrace(error) ?? stackTrace).terse.toString().trimRight());
+    printError(buffer);
     exitCode = 255;
   }
 }
@@ -154,14 +104,3 @@ Future<String> _loadVersion() async {
       .split(" ")
       .last;
 }
-
-/// Delete [path] if it exists and do nothing otherwise.
-///
-/// This is a separate function to work around dart-lang/sdk#53082.
-void _tryDelete(String path) {
-  try {
-    deleteFile(path);
-  } on FileSystemException {
-    // If the file doesn't exist, that's fine.
-  }
-}
diff --git a/lib/src/executable/compile_stylesheet.dart b/lib/src/executable/compile_stylesheet.dart
index 8c24ee494..70b52ba10 100644
--- a/lib/src/executable/compile_stylesheet.dart
+++ b/lib/src/executable/compile_stylesheet.dart
@@ -6,6 +6,7 @@ import 'dart:convert';
 
 import 'package:path/path.dart' as p;
 import 'package:source_maps/source_maps.dart';
+import 'package:stack_trace/stack_trace.dart';
 
 import '../async_import_cache.dart';
 import '../compile.dart';
@@ -30,8 +31,42 @@ import 'options.dart';
 /// If [ifModified] is `true`, only recompiles if [source]'s modification time
 /// or that of a file it imports is more recent than [destination]'s
 /// modification time. Note that these modification times are cached by [graph].
-Future<void> compileStylesheet(ExecutableOptions options, StylesheetGraph graph,
-    String? source, String? destination,
+///
+/// Returns `(exitCode, error, stackTrace)` when an error occurs.
+Future<(int, String, String?)?> compileStylesheet(ExecutableOptions options,
+    StylesheetGraph graph, String? source, String? destination,
+    {bool ifModified = false}) async {
+  try {
+    await _compileStylesheetWithoutErrorHandling(
+        options, graph, source, destination,
+        ifModified: ifModified);
+  } on SassException catch (error, stackTrace) {
+    if (destination != null && !options.emitErrorCss) {
+      _tryDelete(destination);
+    }
+    var message = error.toString(color: options.color);
+
+    // Exit code 65 indicates invalid data per
+    // https://www.freebsd.org/cgi/man.cgi?query=sysexits.
+    return _getErrorWithStackTrace(
+        65, message, options.trace ? getTrace(error) ?? stackTrace : null);
+  } on FileSystemException catch (error, stackTrace) {
+    var path = error.path;
+    var message = path == null
+        ? error.message
+        : "Error reading ${p.relative(path)}: ${error.message}.";
+
+    // Exit code 66 indicates no input.
+    return _getErrorWithStackTrace(
+        66, message, options.trace ? getTrace(error) ?? stackTrace : null);
+  }
+  return null;
+}
+
+/// Like [compileStylesheet], but throws errors instead of handling them
+/// internally.
+Future<void> _compileStylesheetWithoutErrorHandling(ExecutableOptions options,
+    StylesheetGraph graph, String? source, String? destination,
     {bool ifModified = false}) async {
   var importer = FilesystemImporter('.');
   if (ifModified) {
@@ -150,7 +185,7 @@ Future<void> compileStylesheet(ExecutableOptions options, StylesheetGraph graph,
   buffer.write('Compiled $sourceName to $destinationName.');
   if (options.color) buffer.write('\u001b[0m');
 
-  print(buffer);
+  safePrint(buffer);
 }
 
 /// Writes the source map given by [mapping] to disk (if necessary) according to
@@ -195,3 +230,26 @@ String _writeSourceMap(
   return (options.style == OutputStyle.compressed ? '' : '\n\n') +
       '/*# sourceMappingURL=$escapedUrl */';
 }
+
+/// Delete [path] if it exists and do nothing otherwise.
+///
+/// This is a separate function to work around dart-lang/sdk#53082.
+void _tryDelete(String path) {
+  try {
+    deleteFile(path);
+  } on FileSystemException {
+    // If the file doesn't exist, that's fine.
+  }
+}
+
+/// Return a Record of `(exitCode, error, stackTrace)` for the given error.
+(int, String, String?) _getErrorWithStackTrace(
+    int exitCode, String error, StackTrace? stackTrace) {
+  return (
+    exitCode,
+    error,
+    stackTrace != null
+        ? Trace.from(stackTrace).terse.toString().trimRight()
+        : null
+  );
+}
diff --git a/lib/src/executable/concurrent.dart b/lib/src/executable/concurrent.dart
new file mode 100644
index 000000000..f3020f679
--- /dev/null
+++ b/lib/src/executable/concurrent.dart
@@ -0,0 +1,66 @@
+// Copyright 2023 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'dart:math' as math;
+
+import '../io.dart';
+import '../stylesheet_graph.dart';
+import '../util/map.dart';
+import 'compile_stylesheet.dart';
+import 'concurrent/vm.dart'
+    // Never load the isolate library when compiling to JS.
+    if (dart.library.js) 'concurrent/js.dart';
+import 'options.dart';
+
+/// Compiles the stylesheets concurrently and returns whether all stylesheets are compiled
+/// successfully.
+Future<bool> compileStylesheets(ExecutableOptions options,
+    StylesheetGraph graph, Map<String?, String?> sourcesToDestinations,
+    {bool ifModified = false}) async {
+  var errorsWithStackTraces = switch ([...sourcesToDestinations.pairs]) {
+    // Concurrency does add some overhead, so avoid it in the common case of
+    // compiling a single stylesheet.
+    [(var source, var destination)] => [
+        await compileStylesheet(options, graph, source, destination,
+            ifModified: ifModified)
+      ],
+    var pairs => await Future.wait([
+        for (var (source, destination) in pairs)
+          compileStylesheetConcurrently(options, graph, source, destination,
+              ifModified: ifModified)
+      ], eagerError: options.stopOnError)
+  };
+
+  var printedError = false;
+
+  // Print all errors in deterministic order.
+  for (var errorWithStackTrace in errorsWithStackTraces) {
+    if (errorWithStackTrace == null) continue;
+    var (code, error, stackTrace) = errorWithStackTrace;
+
+    // We let the highest exitCode take precedence for deterministic behavior.
+    exitCode = math.max(exitCode, code);
+
+    _printError(error, stackTrace, printedError);
+    printedError = true;
+  }
+
+  return !printedError;
+}
+
+// Prints [error] to stderr, along with a preceding newline if anything else
+// has been printed to stderr.
+//
+// If [stackTrace] is passed, it is printed after the error.
+void _printError(String error, String? stackTrace, bool printedError) {
+  var buffer = StringBuffer();
+  if (printedError) buffer.writeln();
+  buffer.write(error);
+  if (stackTrace != null) {
+    buffer.writeln();
+    buffer.writeln();
+    buffer.write(stackTrace);
+  }
+  printError(buffer);
+}
diff --git a/lib/src/executable/concurrent/js.dart b/lib/src/executable/concurrent/js.dart
new file mode 100644
index 000000000..11cdcb1c1
--- /dev/null
+++ b/lib/src/executable/concurrent/js.dart
@@ -0,0 +1,10 @@
+// Copyright 2023 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import '../compile_stylesheet.dart';
+
+/// We don't currently support concurrent compilation in JS.
+///
+/// In the future, we could add support using web workers.
+final compileStylesheetConcurrently = compileStylesheet;
diff --git a/lib/src/executable/concurrent/vm.dart b/lib/src/executable/concurrent/vm.dart
new file mode 100644
index 000000000..b063b52f0
--- /dev/null
+++ b/lib/src/executable/concurrent/vm.dart
@@ -0,0 +1,33 @@
+// Copyright 2023 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'dart:isolate';
+
+import 'package:term_glyph/term_glyph.dart' as term_glyph;
+
+import '../options.dart';
+import '../../stylesheet_graph.dart';
+import '../compile_stylesheet.dart';
+
+/// Compiles the stylesheet at [source] to [destination].
+///
+/// Runs in a new Dart Isolate, unless [source] is `null`.
+Future<(int, String, String?)?> compileStylesheetConcurrently(
+    ExecutableOptions options,
+    StylesheetGraph graph,
+    String? source,
+    String? destination,
+    {bool ifModified = false}) {
+  // Reading from stdin does not work properly in dart isolate.
+  if (source == null) {
+    return compileStylesheet(options, graph, source, destination,
+        ifModified: ifModified);
+  }
+
+  return Isolate.run(() {
+    term_glyph.ascii = !options.unicode;
+    return compileStylesheet(options, graph, source, destination,
+        ifModified: ifModified);
+  });
+}
diff --git a/lib/src/executable/watch.dart b/lib/src/executable/watch.dart
index 1fc8d9f37..c8a222b0b 100644
--- a/lib/src/executable/watch.dart
+++ b/lib/src/executable/watch.dart
@@ -2,21 +2,16 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
-import 'dart:collection';
-
 import 'package:path/path.dart' as p;
-import 'package:stack_trace/stack_trace.dart';
 import 'package:stream_transform/stream_transform.dart';
 import 'package:watcher/watcher.dart';
 
-import '../exception.dart';
 import '../importer/filesystem.dart';
 import '../io.dart';
 import '../stylesheet_graph.dart';
 import '../util/map.dart';
 import '../util/multi_dir_watcher.dart';
-import '../utils.dart';
-import 'compile_stylesheet.dart';
+import 'concurrent.dart';
 import 'options.dart';
 
 /// Watches all the files in [graph] for changes and updates them as necessary.
@@ -41,15 +36,17 @@ Future<void> watch(ExecutableOptions options, StylesheetGraph graph) async {
   // they currently exist. This ensures that changes that come in update a
   // known-good state.
   var watcher = _Watcher(options, graph);
-  for (var (source, destination) in _sourcesToDestinations(options).pairs) {
+  var sourcesToDestinations = _sourcesToDestinations(options);
+  for (var source in sourcesToDestinations.keys) {
     graph.addCanonical(
         FilesystemImporter('.'), p.toUri(canonicalize(source)), p.toUri(source),
         recanonicalize: false);
-    var success = await watcher.compile(source, destination, ifModified: true);
-    if (!success && options.stopOnError) {
-      dirWatcher.events.listen(null).cancel();
-      return;
-    }
+  }
+  var success = await compileStylesheets(options, graph, sourcesToDestinations,
+      ifModified: true);
+  if (!success && options.stopOnError) {
+    dirWatcher.events.listen(null).cancel();
+    return;
   }
 
   print("Sass is watching for changes. Press Ctrl-C to stop.\n");
@@ -67,34 +64,6 @@ final class _Watcher {
 
   _Watcher(this._options, this._graph);
 
-  /// Compiles the stylesheet at [source] to [destination], and prints any
-  /// errors that occur.
-  ///
-  /// Returns whether or not compilation succeeded.
-  Future<bool> compile(String source, String destination,
-      {bool ifModified = false}) async {
-    try {
-      await compileStylesheet(_options, _graph, source, destination,
-          ifModified: ifModified);
-      return true;
-    } on SassException catch (error, stackTrace) {
-      if (!_options.emitErrorCss) _delete(destination);
-      _printError(
-          error.toString(color: _options.color), getTrace(error) ?? stackTrace);
-      exitCode = 65;
-      return false;
-    } on FileSystemException catch (error, stackTrace) {
-      var path = error.path;
-      _printError(
-          path == null
-              ? error.message
-              : "Error reading ${p.relative(path)}: ${error.message}.",
-          getTrace(error) ?? stackTrace);
-      exitCode = 66;
-      return false;
-    }
-  }
-
   /// Deletes the file at [path] and prints a message about it.
   void _delete(String path) {
     try {
@@ -109,21 +78,6 @@ final class _Watcher {
     }
   }
 
-  /// Prints [message] to standard error, with [stackTrace] if [_options.trace]
-  /// is set.
-  void _printError(String message, StackTrace stackTrace) {
-    var buffer = StringBuffer(message);
-
-    if (_options.trace) {
-      buffer.writeln();
-      buffer.writeln();
-      buffer.write(Trace.from(stackTrace).terse.toString().trimRight());
-    }
-
-    if (!_options.stopOnError) buffer.writeln();
-    printError(buffer);
-  }
-
   /// Listens to `watcher.events` and updates the filesystem accordingly.
   ///
   /// Returns a future that will only complete if an unexpected error occurs.
@@ -172,8 +126,9 @@ final class _Watcher {
   /// Returns whether all necessary recompilations succeeded.
   Future<bool> _handleAdd(String path) async {
     var destination = _destinationFor(path);
-
-    var success = destination == null || await compile(path, destination);
+    var success = destination == null ||
+        await compileStylesheets(_options, _graph, {path: destination},
+            ifModified: true);
     var downstream = _graph.addCanonical(
         FilesystemImporter('.'), _canonicalize(path), p.toUri(path));
     return await _recompileDownstream(downstream) && success;
@@ -226,34 +181,42 @@ final class _Watcher {
   /// Returns whether all recompilations succeeded.
   Future<bool> _recompileDownstream(Iterable<StylesheetNode> nodes) async {
     var seen = <StylesheetNode>{};
-    var toRecompile = Queue.of(nodes);
-
     var allSucceeded = true;
-    while (toRecompile.isNotEmpty) {
-      var node = toRecompile.removeFirst();
-      if (!seen.add(node)) continue;
+    while (nodes.isNotEmpty) {
+      nodes = [
+        for (var node in nodes)
+          if (seen.add(node)) node
+      ];
 
-      var success = await _compileIfEntrypoint(node.canonicalUrl);
-      allSucceeded = allSucceeded && success;
-      if (!success && _options.stopOnError) return false;
+      var sourcesToDestinations = _sourceEntrypointsToDestinations(nodes);
+      if (sourcesToDestinations.isNotEmpty) {
+        var success = await compileStylesheets(
+            _options, _graph, sourcesToDestinations,
+            ifModified: true);
+        if (!success && _options.stopOnError) return false;
 
-      toRecompile.addAll(node.downstream);
+        allSucceeded = allSucceeded && success;
+      }
+
+      nodes = [for (var node in nodes) ...node.downstream];
     }
     return allSucceeded;
   }
 
-  /// Compiles the stylesheet at [url] to CSS if it's an entrypoint that's being
-  /// watched.
-  ///
-  /// Returns `false` if compilation failed, `true` otherwise.
-  Future<bool> _compileIfEntrypoint(Uri url) async {
-    if (url.scheme != 'file') return true;
-
-    var source = p.fromUri(url);
-    return switch (_destinationFor(source)) {
-      var destination? => await compile(source, destination),
-      _ => true
-    };
+  /// Returns a sourcesToDestinations mapping for nodes that are entrypoints.
+  Map<String, String> _sourceEntrypointsToDestinations(
+      Iterable<StylesheetNode> nodes) {
+    var entrypoints = <String, String>{};
+    for (var node in nodes) {
+      var url = node.canonicalUrl;
+      if (url.scheme != 'file') continue;
+
+      var source = p.fromUri(url);
+      if (_destinationFor(source) case var destination?) {
+        entrypoints[source] = destination;
+      }
+    }
+    return entrypoints;
   }
 
   /// If a Sass file at [source] should be compiled to CSS, returns the path to
diff --git a/lib/src/io/interface.dart b/lib/src/io/interface.dart
index 618c3ff6e..be0ec574c 100644
--- a/lib/src/io/interface.dart
+++ b/lib/src/io/interface.dart
@@ -32,8 +32,16 @@ bool get isBrowser => throw '';
 /// sequences.
 bool get supportsAnsiEscapes => throw '';
 
+/// Prints [message] (followed by a newline) to standard output or the
+/// equivalent.
+///
+/// This method is thread-safe.
+void safePrint(Object? message) => throw '';
+
 /// Prints [message] (followed by a newline) to standard error or the
 /// equivalent.
+///
+/// This method is thread-safe.
 void printError(Object? message) => throw '';
 
 /// Reads the file at [path] as a UTF-8 encoded string.
diff --git a/lib/src/io/js.dart b/lib/src/io/js.dart
index efc1955e4..c806dc181 100644
--- a/lib/src/io/js.dart
+++ b/lib/src/io/js.dart
@@ -28,6 +28,14 @@ class FileSystemException {
   String toString() => "${p.prettyUri(p.toUri(path))}: $message";
 }
 
+void safePrint(Object? message) {
+  if (process case var process?) {
+    process.stdout.write("${message ?? ''}\n");
+  } else {
+    console.log(message ?? '');
+  }
+}
+
 void printError(Object? message) {
   if (process case var process?) {
     process.stderr.write("${message ?? ''}\n");
diff --git a/lib/src/io/vm.dart b/lib/src/io/vm.dart
index 0174e09b4..cba88e40f 100644
--- a/lib/src/io/vm.dart
+++ b/lib/src/io/vm.dart
@@ -37,8 +37,21 @@ bool get supportsAnsiEscapes {
   return io.stdout.supportsAnsiEscapes;
 }
 
+void safePrint(Object? message) {
+  _threadSafeWriteLn(io.stdout, message);
+}
+
 void printError(Object? message) {
-  io.stderr.writeln(message);
+  _threadSafeWriteLn(io.stderr, message);
+}
+
+void _threadSafeWriteLn(io.IOSink sink, Object? message) {
+  // This does have performance penality of copying buffer
+  // if message is already a StringBuffer.
+  // https://github.com/dart-lang/sdk/issues/53471.
+  var buffer = StringBuffer(message.toString());
+  buffer.writeln();
+  sink.write(buffer);
 }
 
 String readFile(String path) {
diff --git a/lib/src/parse/parser.dart b/lib/src/parse/parser.dart
index dba0bef99..6dd17c80d 100644
--- a/lib/src/parse/parser.dart
+++ b/lib/src/parse/parser.dart
@@ -9,6 +9,7 @@ import 'package:string_scanner/string_scanner.dart';
 
 import '../exception.dart';
 import '../interpolation_map.dart';
+import '../io.dart';
 import '../logger.dart';
 import '../util/character.dart';
 import '../util/lazy_file_span.dart';
@@ -696,9 +697,9 @@ class Parser {
   @protected
   void debug([Object? message]) {
     if (message == null) {
-      print(scanner.emptySpan.highlight(color: true));
+      safePrint(scanner.emptySpan.highlight(color: true));
     } else {
-      print(scanner.emptySpan.message(message.toString(), color: true));
+      safePrint(scanner.emptySpan.message(message.toString(), color: true));
     }
   }
 
diff --git a/test/cli/shared/colon_args.dart b/test/cli/shared/colon_args.dart
index 88ca8c642..a5ccf314f 100644
--- a/test/cli/shared/colon_args.dart
+++ b/test/cli/shared/colon_args.dart
@@ -97,7 +97,6 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
     await sass.shouldExit(65);
 
     await d.file("out1.css", contains(message)).validate();
-    await d.nothing("out2.css").validate();
   });
 
   group("with a directory argument", () {
diff --git a/test/cli/shared/update.dart b/test/cli/shared/update.dart
index 01aa73949..4fc7bfbc1 100644
--- a/test/cli/shared/update.dart
+++ b/test/cli/shared/update.dart
@@ -66,16 +66,31 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
       await d.file("test2.scss", r"$var: 2; @import 'other'").create();
 
       var sass = await update(["test1.scss:out1.css", "test2.scss:out2.css"]);
-      expect(sass.stdout, emits(endsWith('Compiled test1.scss to out1.css.')));
-      expect(sass.stdout, emits(endsWith('Compiled test2.scss to out2.css.')));
+      expect(
+          sass.stdout,
+          emitsInAnyOrder([
+            endsWith('Compiled test1.scss to out1.css.'),
+            endsWith('Compiled test2.scss to out2.css.')
+          ]));
       await sass.shouldExit(0);
 
+      await d
+          .file("out1.css", equalsIgnoringWhitespace("a { b: 1; }"))
+          .validate();
+      await d
+          .file("out2.css", equalsIgnoringWhitespace("a { b: 2; }"))
+          .validate();
+
       await tick;
       await d.file("other.scss", r"x {y: $var}").create();
 
       sass = await update(["test1.scss:out1.css", "test2.scss:out2.css"]);
-      expect(sass.stdout, emits(endsWith('Compiled test1.scss to out1.css.')));
-      expect(sass.stdout, emits(endsWith('Compiled test2.scss to out2.css.')));
+      expect(
+          sass.stdout,
+          emitsInAnyOrder([
+            endsWith('Compiled test1.scss to out1.css.'),
+            endsWith('Compiled test2.scss to out2.css.')
+          ]));
       await sass.shouldExit(0);
 
       await d
diff --git a/test/cli/shared/watch.dart b/test/cli/shared/watch.dart
index b46fd97a0..b80b33e64 100644
--- a/test/cli/shared/watch.dart
+++ b/test/cli/shared/watch.dart
@@ -3,6 +3,7 @@
 // https://opensource.org/licenses/MIT.
 
 import 'package:path/path.dart' as p;
+import 'package:sass/src/io.dart';
 import 'package:test/test.dart';
 import 'package:test_descriptor/test_descriptor.dart' as d;
 import 'package:test_process/test_process.dart';
@@ -29,7 +30,7 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
     /// Modifying a file very quickly after it was processed can go
     /// unrecognized, especially on Windows where filesystem operations can have
     /// very high delays.
-    Future<void> tickIfPoll() => poll ? tick : Future.value();
+    Future<void> tickIfPoll() => poll || isWindows ? tick : Future.value();
 
     group("${poll ? 'with' : 'without'} --poll", () {
       group("when started", () {
@@ -128,7 +129,6 @@ void sharedTests(Future<TestProcess> runSass(Iterable<String> arguments)) {
           await sass.shouldExit(65);
 
           await d.file("out1.css", contains(message)).validate();
-          await d.nothing("out2.css").validate();
         });
       });