diff --git a/packages/ember-runtime/lib/ext/string.js b/packages/ember-runtime/lib/ext/string.js
index 29bdcceec74..5fec0874f0f 100644
--- a/packages/ember-runtime/lib/ext/string.js
+++ b/packages/ember-runtime/lib/ext/string.js
@@ -25,6 +25,7 @@ if (Ember.EXTEND_PROTOTYPES === true || Ember.EXTEND_PROTOTYPES.String) {
     @method fmt
     @for String
     @private
+    @deprecated
   */
   StringPrototype.fmt = function (...args) {
     return fmt(this, args);
diff --git a/packages/ember-runtime/lib/system/string.js b/packages/ember-runtime/lib/system/string.js
index 3b9b8500300..8a3352d9c57 100644
--- a/packages/ember-runtime/lib/system/string.js
+++ b/packages/ember-runtime/lib/system/string.js
@@ -60,7 +60,7 @@ var DECAMELIZE_CACHE = new Cache(1000, function(str) {
   return str.replace(STRING_DECAMELIZE_REGEXP, '$1_$2').toLowerCase();
 });
 
-function fmt(str, formats) {
+function _fmt(str, formats) {
   var cachedFormats = formats;
 
   if (!isArray(cachedFormats) || arguments.length > 2) {
@@ -80,13 +80,22 @@ function fmt(str, formats) {
   });
 }
 
+function fmt(str, formats) {
+  Ember.deprecate(
+    'Ember.String.fmt is deprecated, use ES6 template strings instead.',
+    false,
+    { id: 'ember-string-utils.fmt', until: '3.0.0', url: 'https://babeljs.io/docs/learn-es6/#template-strings' }
+  );
+  return _fmt(...arguments);
+}
+
 function loc(str, formats) {
   if (!isArray(formats) || arguments.length > 2) {
     formats = Array.prototype.slice.call(arguments, 1);
   }
 
   str = Ember.STRINGS[str] || str;
-  return fmt(str, formats);
+  return _fmt(str, formats);
 }
 
 function w(str) {
diff --git a/packages/ember-runtime/tests/system/string/fmt_string_test.js b/packages/ember-runtime/tests/system/string/fmt_string_test.js
index d16b80b351c..ec588d47f98 100644
--- a/packages/ember-runtime/tests/system/string/fmt_string_test.js
+++ b/packages/ember-runtime/tests/system/string/fmt_string_test.js
@@ -10,6 +10,7 @@ if (!Ember.EXTEND_PROTOTYPES && !Ember.EXTEND_PROTOTYPES.String) {
 }
 
 QUnit.test('\'Hello %@ %@\'.fmt(\'John\', \'Doe\') => \'Hello John Doe\'', function() {
+  expectDeprecation('Ember.String.fmt is deprecated, use ES6 template strings instead.');
   equal(fmt('Hello %@ %@', ['John', 'Doe']), 'Hello John Doe');
   if (Ember.EXTEND_PROTOTYPES) {
     equal('Hello %@ %@'.fmt('John', 'Doe'), 'Hello John Doe');
@@ -17,6 +18,7 @@ QUnit.test('\'Hello %@ %@\'.fmt(\'John\', \'Doe\') => \'Hello John Doe\'', funct
 });
 
 QUnit.test('\'Hello %@2 %@1\'.fmt(\'John\', \'Doe\') => \'Hello Doe John\'', function() {
+  expectDeprecation('Ember.String.fmt is deprecated, use ES6 template strings instead.');
   equal(fmt('Hello %@2 %@1', ['John', 'Doe']), 'Hello Doe John');
   if (Ember.EXTEND_PROTOTYPES) {
     equal('Hello %@2 %@1'.fmt('John', 'Doe'), 'Hello Doe John');
@@ -24,6 +26,7 @@ QUnit.test('\'Hello %@2 %@1\'.fmt(\'John\', \'Doe\') => \'Hello Doe John\'', fun
 });
 
 QUnit.test('\'%@08 %@07 %@06 %@05 %@04 %@03 %@02 %@01\'.fmt(\'One\', \'Two\', \'Three\', \'Four\', \'Five\', \'Six\', \'Seven\', \'Eight\') => \'Eight Seven Six Five Four Three Two One\'', function() {
+  expectDeprecation('Ember.String.fmt is deprecated, use ES6 template strings instead.');
   equal(fmt('%@08 %@07 %@06 %@05 %@04 %@03 %@02 %@01', ['One', 'Two', 'Three', 'Four', 'Five', 'Six', 'Seven', 'Eight']), 'Eight Seven Six Five Four Three Two One');
 
   if (Ember.EXTEND_PROTOTYPES) {
@@ -32,6 +35,7 @@ QUnit.test('\'%@08 %@07 %@06 %@05 %@04 %@03 %@02 %@01\'.fmt(\'One\', \'Two\', \'
 });
 
 QUnit.test('\'data: %@\'.fmt({ id: 3 }) => \'data: {id: 3}\'', function() {
+  expectDeprecation('Ember.String.fmt is deprecated, use ES6 template strings instead.');
   equal(fmt('data: %@', [{ id: 3 }]), 'data: {id: 3}');
   if (Ember.EXTEND_PROTOTYPES) {
     equal('data: %@'.fmt({ id: 3 }), 'data: {id: 3}');
@@ -39,6 +43,7 @@ QUnit.test('\'data: %@\'.fmt({ id: 3 }) => \'data: {id: 3}\'', function() {
 });
 
 QUnit.test('works with argument form', function() {
+  expectDeprecation('Ember.String.fmt is deprecated, use ES6 template strings instead.');
   equal(fmt('%@', 'John'), 'John');
   equal(fmt('%@ %@', ['John'], 'Doe'), '[John] Doe');
 });