diff --git a/src/compiler/commandLineParser.ts b/src/compiler/commandLineParser.ts
index 6de749f2592..ab42aa96bcd 100644
--- a/src/compiler/commandLineParser.ts
+++ b/src/compiler/commandLineParser.ts
@@ -78,6 +78,7 @@ namespace ts {
             name: "module",
             shortName: "m",
             type: {
+                "none": ModuleKind.None,
                 "commonjs": ModuleKind.CommonJS,
                 "amd": ModuleKind.AMD,
                 "system": ModuleKind.System,
@@ -87,7 +88,7 @@ namespace ts {
             },
             description: Diagnostics.Specify_module_code_generation_Colon_commonjs_amd_system_umd_or_es2015,
             paramType: Diagnostics.KIND,
-            error: Diagnostics.Argument_for_module_option_must_be_commonjs_amd_system_umd_or_es2015
+            error: Diagnostics.Argument_for_module_option_must_be_commonjs_amd_system_umd_es2015_or_none
         },
         {
             name: "newLine",
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
index 5b93f61bb90..25b86e67d34 100644
--- a/src/compiler/diagnosticMessages.json
+++ b/src/compiler/diagnosticMessages.json
@@ -447,7 +447,7 @@
         "category": "Error",
         "code": 1147
     },
-    "Cannot compile modules unless the '--module' flag is provided. Consider setting the 'module' compiler option in a 'tsconfig.json' file.": {
+    "Cannot compile modules unless the '--module' flag is provided with a valid module type. Consider setting the 'module' compiler option in a 'tsconfig.json' file.": {
         "category": "Error",
         "code": 1148
     },
@@ -2320,7 +2320,7 @@
         "category": "Error",
         "code": 6045
     },
-    "Argument for '--module' option must be 'commonjs', 'amd', 'system', 'umd', or 'es2015'.": {
+    "Argument for '--module' option must be 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'none'.": {
         "category": "Error",
         "code": 6046
     },
diff --git a/src/compiler/program.ts b/src/compiler/program.ts
index ea8668bfbbc..0acb13f02d3 100644
--- a/src/compiler/program.ts
+++ b/src/compiler/program.ts
@@ -1665,7 +1665,7 @@ namespace ts {
             else if (firstExternalModuleSourceFile && languageVersion < ScriptTarget.ES6 && options.module === ModuleKind.None) {
                 // We cannot use createDiagnosticFromNode because nodes do not have parents yet
                 const span = getErrorSpanForNode(firstExternalModuleSourceFile, firstExternalModuleSourceFile.externalModuleIndicator);
-                programDiagnostics.add(createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, Diagnostics.Cannot_compile_modules_unless_the_module_flag_is_provided_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file));
+                programDiagnostics.add(createFileDiagnostic(firstExternalModuleSourceFile, span.start, span.length, Diagnostics.Cannot_compile_modules_unless_the_module_flag_is_provided_with_a_valid_module_type_Consider_setting_the_module_compiler_option_in_a_tsconfig_json_file));
             }
 
             // Cannot specify module gen target of es6 when below es6