diff --git a/CMakeLists.txt b/CMakeLists.txt
index 719d8b1784..6d2934362e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -122,6 +122,12 @@ set(IGN_RENDERING_VER ${ignition-rendering4_VERSION_MAJOR})
 ign_find_package(ignition-math6 REQUIRED COMPONENTS eigen3 VERSION 6.6)
 set(IGN_MATH_VER ${ignition-math6_VERSION_MAJOR})
 
+#--------------------------------------
+# Find ignition-tools
+ign_find_package(ignition-tools
+                 REQUIRED
+                 PKGCONFIG "ignition-tools")
+
 #--------------------------------------
 # Find protobuf
 set(REQ_PROTOBUF_VER 3)
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 1c029e2900..9cff6aa9b0 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -131,6 +131,36 @@ ign_build_tests(TYPE UNIT
     ignition-gazebo${PROJECT_VERSION_MAJOR}
 )
 
+if(TARGET UNIT_ign_TEST)
+
+  # Running `ign gazebo` on macOS has problems when run with /usr/bin/ruby
+  # due to System Integrity Protection (SIP). Try to find ruby from
+  # homebrew as a workaround.
+  if (APPLE)
+    find_program(BREW_RUBY ruby HINTS /usr/local/opt/ruby/bin)
+  endif()
+
+  add_dependencies(UNIT_ign_TEST
+    ${ign_lib_target}
+    TestModelSystem
+    TestSensorSystem
+    TestWorldSystem
+  )
+
+  target_compile_definitions(UNIT_ign_TEST PRIVATE
+      "BREW_RUBY=\"${BREW_RUBY} \"")
+
+  target_compile_definitions(UNIT_ign_TEST PRIVATE
+      "IGN_PATH=\"${IGNITION-TOOLS_BINARY_DIRS}\"")
+
+  set(_env_vars)
+  list(APPEND _env_vars "IGN_CONFIG_PATH=${CMAKE_BINARY_DIR}/test/conf")
+  list(APPEND _env_vars "IGN_GAZEBO_SYSTEM_PLUGIN_PATH=$<TARGET_FILE_DIR:TestModelSystem>")
+
+  set_tests_properties(UNIT_ign_TEST PROPERTIES
+    ENVIRONMENT "${_env_vars}")
+endif()
+
 if(NOT WIN32)
   add_subdirectory(cmd)
 endif()
diff --git a/src/cmd/cmdgazebo.rb.in b/src/cmd/cmdgazebo.rb.in
index 594e360763..079bfeae19 100755
--- a/src/cmd/cmdgazebo.rb.in
+++ b/src/cmd/cmdgazebo.rb.in
@@ -337,6 +337,17 @@ class Cmd
       Importer.dlload plugin
     rescue DLError => e
       puts "Library error for [#{plugin}]: #{e.to_s}"
+      if plugin.end_with? ".dylib"
+        puts "
+If this script was executed with /usr/bin/ruby, this error may be caused by
+macOS System Integrity Protection. One workaround is to use a different
+version of ruby, for example:
+    brew install ruby
+and add the following line to your shell profile:
+    export PATH=/usr/local/opt/ruby/bin:$PATH
+If you are using a colcon workspace, please ensure that the setup script
+has properly set the DYLD_LIBRARY_PATH environment variables."
+      end
       exit(-1)
     end
 
@@ -435,6 +446,12 @@ class Cmd
       # and gui.
       if options['server'] == 0 && options['gui'] == 0
 
+        if plugin.end_with? ".dylib"
+          puts "`ign gazebo` currently only works with the -s argument on macOS.
+See https://github.com/ignitionrobotics/ign-gazebo/issues/44 for more info."
+          exit(-1)
+        end
+
         serverPid = Process.fork do
           ENV['RMT_PORT'] = '1500'
           Process.setpgid(0, 0)
@@ -484,6 +501,12 @@ class Cmd
             options['file'], options['record-topics'].join(':'))
       # Otherwise run the gui
       else options['gui']
+        if plugin.end_with? ".dylib"
+          puts "`ign gazebo` currently only works with the -s argument on macOS.
+See https://github.com/ignitionrobotics/ign-gazebo/issues/44 for more info."
+          exit(-1)
+        end
+
         ENV['RMT_PORT'] = '1501'
         Importer.runGui(options['gui_config'])
       end
diff --git a/src/ign_TEST.cc b/src/ign_TEST.cc
index c5d0fcdc7f..8bb0986e9d 100644
--- a/src/ign_TEST.cc
+++ b/src/ign_TEST.cc
@@ -26,12 +26,8 @@
 
 static const std::string kBinPath(PROJECT_BINARY_PATH);
 
-// Command line not working on OSX, see
-// https://github.com/ignitionrobotics/ign-gazebo/issues/25/
-#ifndef __APPLE__
 static const std::string kIgnCommand(
-  "IGN_GAZEBO_SYSTEM_PLUGIN_PATH=" + kBinPath + "/lib LD_LIBRARY_PATH=" +
-  kBinPath + "/lib:/usr/local/lib:${LD_LIBRARY_PATH} ign gazebo -s ");
+    std::string(BREW_RUBY) + std::string(IGN_PATH) + "/ign gazebo -s ");
 
 /////////////////////////////////////////////////
 std::string customExecStr(std::string _cmd)
@@ -90,8 +86,7 @@ TEST(CmdLine, Server)
 }
 
 /////////////////////////////////////////////////
-// Not supported on Mac's command line tool
-TEST(CmdLine, IGN_UTILS_TEST_DISABLED_ON_MAC(CachedFuelWorld))
+TEST(CmdLine, CachedFuelWorld)
 {
   std::string projectPath = std::string(PROJECT_SOURCE_PATH) + "/test/worlds";
   setenv("IGN_FUEL_CACHE_PATH", projectPath.c_str(), true);
@@ -164,16 +159,3 @@ TEST(CmdLine, ResourcePath)
   EXPECT_EQ(output.find("Unable to find file plugins.sdf"), std::string::npos)
       << output;
 }
-#endif
-
-/////////////////////////////////////////////////
-/// Main
-int main(int _argc, char **_argv)
-{
-  // Set IGN_CONFIG_PATH to the directory where the .yaml configuration files
-  // is located.
-  setenv("IGN_CONFIG_PATH", IGN_CONFIG_PATH, 1);
-
-  ::testing::InitGoogleTest(&_argc, _argv);
-  return RUN_ALL_TESTS();
-}