diff --git a/src/timepicker/test/timepicker.spec.js b/src/timepicker/test/timepicker.spec.js
index 1b83df5d0f..8a8cac4768 100644
--- a/src/timepicker/test/timepicker.spec.js
+++ b/src/timepicker/test/timepicker.spec.js
@@ -1271,6 +1271,29 @@ describe('timepicker directive', function() {
       expect(element.hasClass('ng-invalid-time')).toBe(false);
     });
 
+    it('should not be invalid when the model is cleared', function() {
+      var elH = getHoursInputEl();
+      var elM = getMinutesInputEl();
+      var elS = getSecondsInputEl();
+
+      $rootScope.time = newTime(10, 20, 30);
+      $rootScope.$digest();
+
+      expect(getModelState()).toEqual([10, 20, 30]);
+
+      changeInputValueTo(elH, '');
+      elH.blur();
+      $rootScope.$digest();
+      changeInputValueTo(elM, '');
+      elM.blur();
+      $rootScope.$digest();
+      changeInputValueTo(elS, '');
+      elS.blur();
+      $rootScope.$digest();
+
+      expect(element.hasClass('ng-invalid-time')).toBe(false);
+    });
+
     it('timepicker1 leaves view alone when hours are invalid and minutes are updated', function() {
       var hoursEl = getHoursInputEl(),
         minutesEl = getMinutesInputEl();
diff --git a/src/timepicker/timepicker.js b/src/timepicker/timepicker.js
index 6a6171d2eb..8c62024a1c 100644
--- a/src/timepicker/timepicker.js
+++ b/src/timepicker/timepicker.js
@@ -166,7 +166,7 @@ angular.module('ui.bootstrap.timepicker', [])
     var hours = +$scope.hours;
     var valid = $scope.showMeridian ? hours > 0 && hours < 13 :
       hours >= 0 && hours < 24;
-    if (!valid) {
+    if (!valid || $scope.hours === '') {
       return undefined;
     }
 
@@ -183,7 +183,11 @@ angular.module('ui.bootstrap.timepicker', [])
 
   function getMinutesFromTemplate() {
     var minutes = +$scope.minutes;
-    return minutes >= 0 && minutes < 60 ? minutes : undefined;
+    var valid = minutes >= 0 && minutes < 60;
+    if (!valid || $scope.minutes === '') {
+      return undefined;
+    }
+    return minutes;
   }
 
   function getSecondsFromTemplate() {
@@ -323,7 +327,9 @@ angular.module('ui.bootstrap.timepicker', [])
 
     hoursInputEl.bind('blur', function(e) {
       ngModelCtrl.$setTouched();
-      if ($scope.hours === null || $scope.hours === '') {
+      if (modelIsEmpty()) {
+        makeValid();
+      } else if ($scope.hours === null || $scope.hours === '') {
         invalidate(true);
       } else if (!$scope.invalidHours && $scope.hours < 10) {
         $scope.$apply(function() {
@@ -353,7 +359,9 @@ angular.module('ui.bootstrap.timepicker', [])
 
     minutesInputEl.bind('blur', function(e) {
       ngModelCtrl.$setTouched();
-      if ($scope.minutes === null) {
+      if (modelIsEmpty()) {
+        makeValid();
+      } else if ($scope.minutes === null) {
         invalidate(undefined, true);
       } else if (!$scope.invalidMinutes && $scope.minutes < 10) {
         $scope.$apply(function() {
@@ -376,7 +384,9 @@ angular.module('ui.bootstrap.timepicker', [])
     };
 
     secondsInputEl.bind('blur', function(e) {
-      if (!$scope.invalidSeconds && $scope.seconds < 10) {
+      if (modelIsEmpty()) {
+        makeValid();
+      } else if (!$scope.invalidSeconds && $scope.seconds < 10) {
         $scope.$apply( function() {
           $scope.seconds = pad($scope.seconds);
         });
@@ -465,6 +475,12 @@ angular.module('ui.bootstrap.timepicker', [])
     return newDate;
   }
 
+  function modelIsEmpty() {
+    return ($scope.hours === null || $scope.hours === '') &&
+      ($scope.minutes === null || $scope.minutes === '') &&
+      (!$scope.showSeconds || $scope.showSeconds && ($scope.seconds === null || $scope.seconds === ''));
+  }
+
   $scope.showSpinners = angular.isDefined($attrs.showSpinners) ?
     $scope.$parent.$eval($attrs.showSpinners) : timepickerConfig.showSpinners;