diff --git a/NEWS b/NEWS
index 2f84ee83..61a5715d 100644
--- a/NEWS
+++ b/NEWS
@@ -3,6 +3,8 @@
   * Fixed a bug with the `activate' CLI command. Thanks to Joffrey Jaffeux for
     the patch.
   * Added a feature to support Subscripting (Objective-C Literals).
+  * Made the REPL for a OS X application work in development mode when it is
+    sandboxed.
 
 = RubyMotion 2.22 =
 
diff --git a/bin/sim.m b/bin/sim.m
index 3f9b12ce..9498ced2 100644
--- a/bin/sim.m
+++ b/bin/sim.m
@@ -1334,16 +1334,20 @@ main(int argc, char **argv)
 	environment] mutableCopy];
     if (debug_mode != DEBUG_NOTHING) {
 	// Prepare repl socket path.
-	NSString *tmpdir = NSTemporaryDirectory();
-	assert(tmpdir != nil);
-	char path[PATH_MAX];
-	snprintf(path, sizeof path, "%s/rubymotion-repl-XXXXXX",
-		[tmpdir fileSystemRepresentation]);
-	assert(mktemp(path) != NULL);
-	replSocketPath = [[[NSFileManager defaultManager]
-	    stringWithFileSystemRepresentation:path length:strlen(path)]
-	    retain];
-	[appEnvironment setObject:replSocketPath forKey:@"REPL_SOCKET_PATH"];
+	replSocketPath = [appEnvironment[@"REPL_SOCKET_PATH"] retain];
+	if (replSocketPath == nil) {
+	    NSString *tmpdir = NSTemporaryDirectory();
+	    assert(tmpdir != nil);
+	    char path[PATH_MAX];
+	    snprintf(path, sizeof path, "%s/rubymotion-repl-XXXXXX",
+		    [tmpdir fileSystemRepresentation]);
+	    assert(mktemp(path) != NULL);
+	    replSocketPath = [[[NSFileManager defaultManager]
+		stringWithFileSystemRepresentation:path length:strlen(path)]
+		retain];
+	    [appEnvironment setObject:replSocketPath
+			       forKey:@"REPL_SOCKET_PATH"];
+	}
 
 	// Make sure the unix socket path does not exist.
 	[[NSFileManager defaultManager] removeItemAtPath:replSocketPath
diff --git a/lib/motion/project/template/osx.rb b/lib/motion/project/template/osx.rb
index 77def4fe..0f150a76 100644
--- a/lib/motion/project/template/osx.rb
+++ b/lib/motion/project/template/osx.rb
@@ -58,7 +58,10 @@ task :run do
   end
   exec = App.config.app_bundle_executable('MacOSX')
   env = ''
-  env << 'SIM_SPEC_MODE=1' if App.config.spec_mode
+  env << 'SIM_SPEC_MODE=1 ' if App.config.spec_mode
+  if App.config.needs_repl_sandbox_entitlements?
+    env << "REPL_SOCKET_PATH='#{App.config.app_sandbox_repl_socket_path}' "
+  end
   sim = File.join(App.config.bindir, 'osx/sim')
   debug = (ENV['debug'] ? 1 : (App.config.spec_mode ? '0' : '2'))
   target = App.config.sdk_version
diff --git a/lib/motion/project/template/osx/config.rb b/lib/motion/project/template/osx/config.rb
index 9c63acbc..ef8fb024 100644
--- a/lib/motion/project/template/osx/config.rb
+++ b/lib/motion/project/template/osx/config.rb
@@ -100,8 +100,16 @@ module Motion; module Project;
       super('Mac')
     end
 
+    def needs_repl_sandbox_entitlements?
+      development? && codesign_for_development && entitlements['com.apple.security.app-sandbox']
+    end
+
     def entitlements_data
-      dict = entitlements
+      dict = entitlements.dup
+      if needs_repl_sandbox_entitlements?
+        files = (dict['com.apple.security.temporary-exception.files.absolute-path.read-only'] ||= [])
+        files << datadir('librubymotion-repl.dylib')
+      end
       Motion::PropertyList.to_s(dict)
     end
 
@@ -135,6 +143,10 @@ module Motion; module Project;
       File.join(app_bundle(platform), 'Resources')
     end
 
+    def app_sandbox_repl_socket_path
+      File.expand_path(File.join('~/Library/Containers', identifier, "Data/rubymotion-repl-#{Time.now.to_i}"))
+    end
+
     def info_plist_data(platform)
       Motion::PropertyList.to_s({
         'NSHumanReadableCopyright' => copyright,