diff --git a/types/ember/index.d.ts b/types/ember/index.d.ts
index 3ff82919dc..cee4ebc780 100755
--- a/types/ember/index.d.ts
+++ b/types/ember/index.d.ts
@@ -324,6 +324,17 @@ declare module 'ember' {
 
         interface ArrayPrototypeExtensions<T> extends MutableArray<T>, Observable, Copyable {}
 
+        interface StringPrototypeExtensions {
+            camelize(): string;
+            decamelize(): string;
+            classify(): string;
+            capitalize(): string;
+            loc(values?: string[]): string;
+            dasherize(): string;
+            underscore(): string;
+            w(): string[];
+        }
+
         /**
          * Given a fullName return a factory manager.
          */
@@ -2453,7 +2464,7 @@ declare module 'ember' {
             function fmt(...args: string[]): string;
             function htmlSafe(str: string): Handlebars.SafeString;
             function isHTMLSafe(str: string): boolean;
-            function loc(...args: string[]): string;
+            function loc(template: string, args?: string[]): string;
             function underscore(str: string): string;
             function w(str: string): string[];
         }
diff --git a/types/ember/test/string-ext.ts b/types/ember/test/string-ext.ts
new file mode 100644
index 0000000000..e4ac77d5b4
--- /dev/null
+++ b/types/ember/test/string-ext.ts
@@ -0,0 +1,28 @@
+import Ember from 'ember';
+
+declare global {
+    interface String extends Ember.StringPrototypeExtensions {}
+}
+
+''.dasherize('foo'); // $ExpectError
+''.dasherize(); // $ExpectType string
+
+''.camelize(); // $ExpectType string
+''.camelize('blue man group'); // $ExpectError
+
+''.decamelize(); // $ExpectType string
+''.decamelize('blue man group'); // $ExpectError
+
+''.underscore(); // $ExpectType string
+''.underscore('blue man group'); // $ExpectError
+
+''.w(); // $ExpectType string[]
+
+''.classify(); // $ExpectType string
+''.classify('blue man group'); // $ExpectError
+
+''.capitalize(); // $ExpectType string
+''.capitalize('blue man group'); // $ExpectError
+
+''.loc(); // $ExpectType string
+''.loc("_Hello World");  // $ExpectError
diff --git a/types/ember/test/string.ts b/types/ember/test/string.ts
new file mode 100644
index 0000000000..0543bd60d0
--- /dev/null
+++ b/types/ember/test/string.ts
@@ -0,0 +1,36 @@
+import Ember from 'ember';
+
+const { dasherize, camelize, capitalize, classify, decamelize, htmlSafe, loc, underscore, w } = Ember.String;
+
+dasherize(); // $ExpectError
+dasherize('blue man group'); // $ExpectType string
+dasherize('', ''); // $ExpectError
+
+camelize(); // $ExpectError
+camelize('blue man group'); // $ExpectType string
+camelize('', ''); // $ExpectError
+
+decamelize(); // $ExpectError
+decamelize('blue man group'); // $ExpectType string
+decamelize('', ''); // $ExpectError
+
+underscore(); // $ExpectError
+underscore('blue man group'); // $ExpectType string
+underscore('', ''); // $ExpectError
+
+w(); // $ExpectError
+w('blue man group'); // $ExpectType string[]
+w('', ''); // $ExpectError
+
+classify(); // $ExpectError
+classify('blue man group'); // $ExpectType string
+classify('', ''); // $ExpectError
+
+capitalize(); // $ExpectError
+capitalize('blue man group'); // $ExpectType string
+capitalize('', ''); // $ExpectError
+
+loc(); // $ExpectError
+loc("_Hello World");  // $ExpectType string
+// TODO - fix this case upstream in @types/ember https://github.com/typed-ember/ember-cli-typescript/issues/281
+loc("_Hello %@ %@", ["John", "Smith"]);  // $ExpectType string
diff --git a/types/ember/tsconfig.json b/types/ember/tsconfig.json
index 29f20bcc44..74ec227219 100755
--- a/types/ember/tsconfig.json
+++ b/types/ember/tsconfig.json
@@ -21,39 +21,41 @@
     "files": [
         "index.d.ts",
         "test/lib/assert.ts",
-        "test/application.ts",
         "test/access-modifier.ts",
         "test/application-instance.ts",
-        "test/engine.ts",
-        "test/engine-instance.ts",
+        "test/application.ts",
+        "test/array-ext.ts",
+        "test/array-proxy.ts",
+        "test/array.ts",
+        "test/component.ts",
+        "test/computed.ts",
+        "test/controller.ts",
+        "test/create-negative.ts",
+        "test/create.ts",
+        "test/create.ts",
+        "test/detect-instance.ts",
+        "test/detect.ts",
         "test/ember-tests.ts",
+        "test/engine-instance.ts",
+        "test/engine.ts",
         "test/error.ts",
         "test/event.ts",
         "test/extend.ts",
-        "test/create.ts",
-        "test/create-negative.ts",
-        "test/create.ts",
+        "test/function-ext.ts",
+        "test/helper.ts",
+        "test/inject.ts",
+        "test/mixin.ts",
         "test/object.ts",
         "test/observable.ts",
-        "test/mixin.ts",
         "test/reopen.ts",
-        "test/detect.ts",
-        "test/detect-instance.ts",
-        "test/array.ts",
-        "test/array-ext.ts",
-        "test/array-proxy.ts",
-        "test/helper.ts",
-        "test/computed.ts",
-        "test/component.ts",
-        "test/function-ext.ts",
-        "test/inject.ts",
-        "test/utils.ts",
-        "test/transition.ts",
+        "test/route.ts",
         "test/router.ts",
         "test/run.ts",
+        "test/string.ts",
+        "test/string-ext.ts",
         "test/test.ts",
-        "test/controller.ts",
-        "test/route.ts",
+        "test/transition.ts",
+        "test/utils.ts",
         "test/view-utils.ts"
     ]
 }