diff --git a/tools/handlertree.pl b/tools/handlertree.pl
new file mode 100644
index 0000000000..ff5c06b1d9
--- /dev/null
+++ b/tools/handlertree.pl
@@ -0,0 +1,140 @@
+#!/usr/bin/perl -w
+#
+# handlertree.pl
+# ~~~~~~~~~~~~~~
+# A tool for post-processing the debug output generated by Asio-based programs
+# to print the tree of handlers that resulted in some specified handler ids.
+# Programs write this output to the standard error stream when compiled with
+# the define `BOOST_ASIO_ENABLE_HANDLER_TRACKING'.
+#
+# Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+#
+# Distributed under the Boost Software License, Version 1.0. (See accompanying
+# file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#
+
+use strict;
+
+my %target_handlers = ();
+my @cached_output = ();
+my %outstanding_handlers = ();
+my %running_handlers = ();
+
+#-------------------------------------------------------------------------------
+# Build the initial list of target handlers from the command line arguments.
+
+sub build_initial_target_handlers()
+{
+  for my $handler (@ARGV)
+  {
+    $target_handlers{$handler} = 1;
+  }
+}
+
+#-------------------------------------------------------------------------------
+# Parse the debugging output and cache the handler tracking lines.
+
+sub parse_debug_output()
+{
+  while (my $line = <STDIN>)
+  {
+    chomp($line);
+
+    if ($line =~ /\@asio\|([^|]*)\|([^|]*)\|(.*)$/)
+    {
+      push(@cached_output, $line);
+    }
+  }
+}
+
+#-------------------------------------------------------------------------------
+# Iterate over the cached output in revese and build a hash of all target
+# handlers' ancestors.
+
+sub build_target_handler_tree()
+{
+  my $i = scalar(@cached_output) - 1;
+  while ($i >= 0)
+  {
+    my $line = $cached_output[$i];
+
+    if ($line =~ /\@asio\|([^|]*)\|([^|]*)\|(.*)$/)
+    {
+      my $action = $2;
+
+      # Handler creation.
+      if ($action =~ /^([0-9]+)\*([0-9]+)$/)
+      {
+        if ($1 ne "0" and exists($target_handlers{$2}))
+        {
+          $target_handlers{$1} = 1;
+        }
+      }
+    }
+
+    --$i;
+  }
+}
+
+#-------------------------------------------------------------------------------
+# Print out all handler tracking records associated with the target handlers.
+
+sub print_target_handler_records()
+{
+  for my $line (@cached_output)
+  {
+    if ($line =~ /\@asio\|([^|]*)\|([^|]*)\|(.*)$/)
+    {
+      my $action = $2;
+
+      # Handler location.
+      if ($action =~ /^([0-9]+)\^([0-9]+)$/)
+      {
+        print("$line\n") if ($1 eq "0" or exists($target_handlers{$1})) and exists($target_handlers{$2});
+      }
+
+      # Handler creation.
+      if ($action =~ /^([0-9]+)\*([0-9]+)$/)
+      {
+        print("$1, $2, $line\n") if ($1 eq "0" or exists($target_handlers{$1})) and exists($target_handlers{$2});
+      }
+
+      # Begin handler invocation. 
+      elsif ($action =~ /^>([0-9]+)$/)
+      {
+        print("$line\n") if (exists($target_handlers{$1}));
+      }
+
+      # End handler invocation.
+      elsif ($action =~ /^<([0-9]+)$/)
+      {
+        print("$line\n") if (exists($target_handlers{$1}));
+      }
+
+      # Handler threw exception.
+      elsif ($action =~ /^!([0-9]+)$/)
+      {
+        print("$line\n") if (exists($target_handlers{$1}));
+      }
+
+      # Handler was destroyed without being invoked.
+      elsif ($action =~ /^~([0-9]+)$/)
+      {
+        print("$line\n") if (exists($target_handlers{$1}));
+      }
+
+      # Operation associated with a handler.
+      elsif ($action =~ /^\.([0-9]+)$/)
+      {
+        print("$line\n") if (exists($target_handlers{$1}));
+      }
+    }
+  }
+}
+
+#-------------------------------------------------------------------------------
+
+build_initial_target_handlers();
+parse_debug_output();
+build_target_handler_tree();
+print_target_handler_records();