diff --git a/gulpfile.js b/gulpfile.js
index 16186a93f68..090cdd4f2a1 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -177,6 +177,10 @@ gulp.task('lib', ['clean:lib'], function () {
                 paths.npmDir + 'angulartics/src/angulartics.js'
             ],
             dest: paths.libDir + 'angulartics'
+        },
+        {
+            src: paths.npmDir + 'duo_web_sdk/index.js',
+            dest: paths.libDir + 'duo'
         }
     ];
 
diff --git a/package.json b/package.json
index 03e840decde..4259a1f2dce 100644
--- a/package.json
+++ b/package.json
@@ -48,6 +48,7 @@
     "browserify": "14.1.0",
     "vinyl-source-stream": "1.1.0",
     "gulp-derequire": "2.1.0",
-    "exposify": "0.5.0"
+    "exposify": "0.5.0",
+    "duo_web_sdk": "git+https://github.com/duosecurity/duo_web_sdk.git"
   }
 }
diff --git a/src/app/accounts/accountsLoginController.js b/src/app/accounts/accountsLoginController.js
index 1917538c882..cc25604c2a6 100644
--- a/src/app/accounts/accountsLoginController.js
+++ b/src/app/accounts/accountsLoginController.js
@@ -57,6 +57,7 @@ angular
                     $state.go('frontend.login.twoFactor', { returnState: returnState }).then(function () {
                         $timeout(function () {
                             $("#code").focus();
+                            init();
                         });
                     });
                 }
@@ -90,6 +91,7 @@ angular
                 $scope.twoFactorProvider = provider;
                 $timeout(function () {
                     $("#code").focus();
+                    init();
                 });
             });
         };
@@ -102,4 +104,19 @@ angular
                 $state.go('backend.user.vault');
             }
         }
+
+        function init() {
+            if ($scope.twoFactorProvider === constants.twoFactorProvider.duo) {
+                var params = $scope.twoFactorProviders[constants.twoFactorProvider.duo];
+
+                Duo.init({
+                    host: params.Host,
+                    sig_request: params.Signature,
+                    submit_callback: function (theForm) {
+                        var response = $(theForm).find('input[name="sig_response"]').val();
+                        $scope.twoFactor(response);
+                    }
+                });
+            }
+        }
     });
diff --git a/src/app/accounts/views/accountsLoginTwoFactor.html b/src/app/accounts/views/accountsLoginTwoFactor.html
index ead9d22fc80..aef91aadf5f 100644
--- a/src/app/accounts/views/accountsLoginTwoFactor.html
+++ b/src/app/accounts/views/accountsLoginTwoFactor.html
@@ -57,3 +57,30 @@
         </div>
     </form>
 </div>
+
+<div ng-if="twoFactorProvider === 2">
+    <p class="login-box-msg">
+        Complete logging in with Duo.
+    </p>
+    <form name="twoFactorForm" ng-submit="twoFactorForm.$valid && twoFactor(token)" api-form="twoFactorPromise">
+        <div class="callout callout-danger validation-errors" ng-show="twoFactorForm.$errors">
+            <h4>Errors have occurred</h4>
+            <ul>
+                <li ng-repeat="e in twoFactorForm.$errors">{{e}}</li>
+            </ul>
+        </div>
+        <div id="duoFrameWrapper">
+            <iframe id="duo_iframe"></iframe>
+        </div>
+        <div class="row">
+            <div class="col-xs-7">
+                <a stop-click href="#" ng-click="anotherMethod()">Use another method?</a>
+            </div>
+            <div class="col-xs-5">
+                <button type="submit" class="btn btn-primary btn-block btn-flat" ng-disabled="twoFactorForm.$loading">
+                    <i class="fa fa-refresh fa-spin loading-icon" ng-show="twoFactorForm.$loading"></i>Log In
+                </button>
+            </div>
+        </div>
+    </form>
+</div>
diff --git a/src/app/services/apiService.js b/src/app/services/apiService.js
index 511ec7f222b..27b7e404c18 100644
--- a/src/app/services/apiService.js
+++ b/src/app/services/apiService.js
@@ -114,11 +114,13 @@
         _service.twoFactor = $resource(_apiUri + '/two-factor', {}, {
             list: { method: 'GET', params: {} },
             getEmail: { url: _apiUri + '/two-factor/get-email', method: 'POST', params: {} },
+            getDuo: { url: _apiUri + '/two-factor/get-duo', method: 'POST', params: {} },
             getAuthenticator: { url: _apiUri + '/two-factor/get-authenticator', method: 'POST', params: {} },
             getYubi: { url: _apiUri + '/two-factor/get-yubikey', method: 'POST', params: {} },
             sendEmail: { url: _apiUri + '/two-factor/send-email', method: 'POST', params: {} },
             putEmail: { url: _apiUri + '/two-factor/email', method: 'POST', params: {} },
             putAuthenticator: { url: _apiUri + '/two-factor/authenticator', method: 'POST', params: {} },
+            putDuo: { url: _apiUri + '/two-factor/duo', method: 'POST', params: {} },
             putYubi: { url: _apiUri + '/two-factor/yubikey', method: 'POST', params: {} },
             disable: { url: _apiUri + '/two-factor/disable', method: 'POST', params: {} },
             recover: { url: _apiUri + '/two-factor/recover', method: 'POST', params: {} },
diff --git a/src/app/settings/settingsTwoStepAuthenticatorController.js b/src/app/settings/settingsTwoStepAuthenticatorController.js
index bec1dfa4a78..97eb22cb43a 100644
--- a/src/app/settings/settingsTwoStepAuthenticatorController.js
+++ b/src/app/settings/settingsTwoStepAuthenticatorController.js
@@ -7,7 +7,7 @@
         var _issuer = 'bitwarden',
             _profile = null,
             _masterPasswordHash
-            _key = null;
+        _key = null;
 
         $scope.auth = function (model) {
             _masterPasswordHash = cryptoService.hashPassword(model.masterPassword);
@@ -69,6 +69,7 @@
             }, function (response) {
                 $analytics.eventTrack('Disabled Two-step Authenticator');
                 toastr.success('Authenticator app has been disabled.');
+                $scope.enabled = response.Enabled;
                 $scope.close();
             }).$promise;
         }
@@ -86,6 +87,6 @@
         }
 
         $scope.close = function () {
-            $uibModalInstance.close();
+            $uibModalInstance.close($scope.enabled);
         };
     });
diff --git a/src/app/settings/settingsTwoStepController.js b/src/app/settings/settingsTwoStepController.js
index 26aed1cb561..620c22f2192 100644
--- a/src/app/settings/settingsTwoStepController.js
+++ b/src/app/settings/settingsTwoStepController.js
@@ -65,8 +65,8 @@
                     }
                 });
 
-                authenticatorModal.result.then(function () {
-                    
+                authenticatorModal.result.then(function (enabled) {
+                    provider.enabled = enabled;
                 });
             }
             else if(provider.type === constants.twoFactorProvider.email) {
@@ -79,8 +79,8 @@
                     }
                 });
 
-                emailModal.result.then(function () {
-
+                emailModal.result.then(function (enabled) {
+                    provider.enabled = enabled;
                 });
             }
             else if (provider.type === constants.twoFactorProvider.yubikey) {
@@ -93,8 +93,22 @@
                     }
                 });
 
-                yubiModal.result.then(function () {
+                yubiModal.result.then(function (enabled) {
+                    provider.enabled = enabled;
+                });
+            }
+            else if (provider.type === constants.twoFactorProvider.duo) {
+                var yubiModal = $uibModal.open({
+                    animation: true,
+                    templateUrl: 'app/settings/views/settingsTwoStepDuo.html',
+                    controller: 'settingsTwoStepDuoController',
+                    resolve: {
+                        enabled: function () { return provider.enabled; }
+                    }
+                });
 
+                yubiModal.result.then(function (enabled) {
+                    provider.enabled = enabled;
                 });
             }
         };
diff --git a/src/app/settings/settingsTwoStepDuoController.js b/src/app/settings/settingsTwoStepDuoController.js
new file mode 100644
index 00000000000..e073d6b0467
--- /dev/null
+++ b/src/app/settings/settingsTwoStepDuoController.js
@@ -0,0 +1,75 @@
+angular
+    .module('bit.settings')
+
+    .controller('settingsTwoStepDuoController', function ($scope, apiService, $uibModalInstance, cryptoService,
+        toastr, $analytics, constants) {
+        $analytics.eventTrack('settingsTwoStepDuoController', { category: 'Modal' });
+        var _masterPasswordHash;
+
+        $scope.updateModel = {
+            token: null,
+            host: null,
+            ikey: null,
+            skey: null
+        };
+
+        $scope.auth = function (model) {
+            _masterPasswordHash = cryptoService.hashPassword(model.masterPassword);
+            $scope.authPromise = apiService.twoFactor.getDuo({}, {
+                masterPasswordHash: _masterPasswordHash
+            }).$promise.then(function (apiResponse) {
+                processResult(apiResponse);
+                $scope.authed = true;
+            });
+        };
+
+        $scope.submit = function (model) {
+            if ($scope.enabled) {
+                disable();
+                return;
+            }
+
+            update(model);
+        };
+
+        function disable() {
+            if (!confirm('Are you sure you want to disable the Duo provider?')) {
+                return;
+            }
+
+            $scope.submitPromise = apiService.twoFactor.disable({}, {
+                masterPasswordHash: _masterPasswordHash,
+                type: constants.twoFactorProvider.duo
+            }, function (response) {
+                $analytics.eventTrack('Disabled Two-step Duo');
+                toastr.success('Duo has been disabled.');
+                $scope.enabled = response.Enabled;
+                $scope.close();
+            }).$promise;
+        }
+
+        function update(model) {
+            $scope.submitPromise = apiService.twoFactor.putDuo({}, {
+                integrationKey: model.ikey,
+                secretKey: model.skey,
+                host: model.host,
+                masterPasswordHash: _masterPasswordHash
+            }, function (response) {
+                $analytics.eventTrack('Enabled Two-step Duo');
+                processResult(response);
+            }).$promise;
+        }
+
+        function processResult(response) {
+            $scope.enabled = response.Enabled;
+            $scope.updateModel = {
+                ikey: response.IntegrationKey,
+                skey: response.SecretKey,
+                host: response.Host
+            };
+        }
+
+        $scope.close = function () {
+            $uibModalInstance.close($scope.enabled);
+        };
+    });
diff --git a/src/app/settings/settingsTwoStepEmailController.js b/src/app/settings/settingsTwoStepEmailController.js
index 04d30409bef..5eb0dfb8075 100644
--- a/src/app/settings/settingsTwoStepEmailController.js
+++ b/src/app/settings/settingsTwoStepEmailController.js
@@ -74,6 +74,7 @@
             }, function (response) {
                 $analytics.eventTrack('Disabled Two-step Email');
                 toastr.success('Email has been disabled.');
+                $scope.enabled = response.Enabled;
                 $scope.close();
             }).$promise;
         }
@@ -92,6 +93,6 @@
         }
 
         $scope.close = function () {
-            $uibModalInstance.close();
+            $uibModalInstance.close($scope.enabled);
         };
     });
diff --git a/src/app/settings/settingsTwoStepYubiController.js b/src/app/settings/settingsTwoStepYubiController.js
index 77943fe7361..a9f606c74b7 100644
--- a/src/app/settings/settingsTwoStepYubiController.js
+++ b/src/app/settings/settingsTwoStepYubiController.js
@@ -56,6 +56,7 @@
                 $scope.disableLoading = false;
                 $analytics.eventTrack('Disabled Two-step YubiKey');
                 toastr.success('YubiKey has been disabled.');
+                $scope.enabled = response.Enabled;
                 $scope.close();
             }, function (response) {
                 toastr.error('Failed to disable.');
@@ -102,6 +103,6 @@
         }
 
         $scope.close = function () {
-            $uibModalInstance.close();
+            $uibModalInstance.close($scope.enabled);
         };
     });
diff --git a/src/app/settings/views/settingsTwoStepDuo.html b/src/app/settings/views/settingsTwoStepDuo.html
new file mode 100644
index 00000000000..82fc6a6ac42
--- /dev/null
+++ b/src/app/settings/views/settingsTwoStepDuo.html
@@ -0,0 +1,76 @@
+<div class="modal-header">
+    <button type="button" class="close" ng-click="close()" aria-label="Close"><span aria-hidden="true">&times;</span></button>
+    <h4 class="modal-title">
+        <i class="fa fa-key"></i> Two-step Login <small>duo</small>
+    </h4>
+</div>
+<form name="authTwoStepForm" ng-submit="authTwoStepForm.$valid && auth(authModel)" api-form="authPromise"
+      ng-if="!authed">
+    <div class="modal-body">
+        <p>Enter your master password to modify two-step login settings.</p>
+        <div class="callout callout-danger validation-errors" ng-show="authTwoStepForm.$errors">
+            <h4>Errors have occurred</h4>
+            <ul>
+                <li ng-repeat="e in authTwoStepForm.$errors">{{e}}</li>
+            </ul>
+        </div>
+        <div class="form-group" show-errors>
+            <label for="masterPassword">Master Password</label>
+            <input type="password" id="masterPassword" name="MasterPasswordHash" ng-model="authModel.masterPassword"
+                   class="form-control" required api-field />
+        </div>
+    </div>
+    <div class="modal-footer">
+        <button type="submit" class="btn btn-primary btn-flat" ng-disabled="authTwoStepForm.$loading">
+            <i class="fa fa-refresh fa-spin loading-icon" ng-show="authTwoStepForm.$loading"></i>Continue
+        </button>
+        <button type="button" class="btn btn-default btn-flat" ng-click="close()">Close</button>
+    </div>
+</form>
+<form name="submitTwoStepForm" ng-submit="submitTwoStepForm.$valid && submit(updateModel)" api-form="submitPromise"
+      ng-if="authed">
+    <div class="modal-body">
+        <div ng-if="enabled">
+            <div class="callout callout-success">
+                <h4><i class="fa fa-check-circle"></i> Enabled</h4>
+                <p>Two-step log via Duo is enabled on your account.</p>
+            </div>
+            <ul class="list-unstyled">
+                <li><strong>Integration Key:</strong> {{updateModel.ikey}}</li>
+                <li><strong>Secret Key:</strong> ************</li>
+                <li><strong>API Hostname:</strong> {{updateModel.host}}</li>
+            </ul>
+        </div>
+        <div ng-if="!enabled">
+            <div class="callout callout-danger validation-errors" ng-show="submitTwoStepForm.$errors">
+                <h4>Errors have occurred</h4>
+                <ul>
+                    <li ng-repeat="e in submitTwoStepForm.$errors">{{e}}</li>
+                </ul>
+            </div>
+            <p>Setting up two-step login with Duo is easy, just enter the Duo application information below:</p>
+            <div class="form-group" show-errors>
+                <label for="ikey">Integration Key</label>
+                <input type="text" id="ikey" name="IntegrationKey" ng-model="updateModel.ikey" class="form-control"
+                       required api-field />
+            </div>
+            <div class="form-group" show-errors>
+                <label for="skey">Secret Key</label>
+                <input type="password" id="skey" name="SecretKey" ng-model="updateModel.skey" class="form-control"
+                       required api-field />
+            </div>
+            <div class="form-group" show-errors>
+                <label for="host">API Hostname</label>
+                <input type="text" id="host" name="Host" placeholder="ex. api-xxxxxxxx.duosecurity.com"
+                       ng-model="updateModel.host" class="form-control" required api-field />
+            </div>
+        </div>
+    </div>
+    <div class="modal-footer">
+        <button type="submit" class="btn btn-primary btn-flat" ng-disabled="submitTwoStepForm.$loading">
+            <i class="fa fa-refresh fa-spin loading-icon" ng-show="submitTwoStepForm.$loading"></i>
+            {{enabled ? 'Disable' : 'Enable'}}
+        </button>
+        <button type="button" class="btn btn-default btn-flat" ng-click="close()">Close</button>
+    </div>
+</form>
diff --git a/src/images/loading.svg b/src/images/loading.svg
new file mode 100644
index 00000000000..70763105168
--- /dev/null
+++ b/src/images/loading.svg
@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" width="100%" height="100%" viewBox="0 0 100% 100%">
+  <text fill="%23333333" x="50%" y="50%" font-family="\'Open Sans\', \'Helvetica Neue\', Helvetica, Arial, sans-serif"
+        font-size="18" text-anchor="middle">
+    Loading...
+  </text>
+</svg>
diff --git a/src/index.html b/src/index.html
index 41f1e7f806b..c93b7243bf5 100644
--- a/src/index.html
+++ b/src/index.html
@@ -29,10 +29,12 @@
             https://fonts.gstatic.com;
           child-src
             'self'
-            https://js.stripe.com;
+            https://js.stripe.com
+            https://*.duosecurity.com;
           frame-src
             'self'
-            https://js.stripe.com;
+            https://js.stripe.com
+            https://*.duosecurity.com;
           connect-src
             *;">
     <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
@@ -85,6 +87,7 @@
     <script src="lib/forge/forge.js"></script>
     <script src="lib/papaparse/papaparse.js"></script>
     <script src="lib/clipboard/clipboard.js"></script>
+    <script src="lib/duo/index.js"></script>
 
     <script src="lib/angular/angular.js"></script>
     <script src="lib/angular-cookies/angular-cookies.js"></script>
@@ -190,6 +193,7 @@
     <script src="app/settings/settingsChangePasswordController.js"></script>
     <script src="app/settings/settingsChangeEmailController.js"></script>
     <script src="app/settings/settingsTwoStepAuthenticatorController.js"></script>
+    <script src="app/settings/settingsTwoStepDuoController.js"></script>
     <script src="app/settings/settingsTwoStepEmailController.js"></script>
     <script src="app/settings/settingsTwoStepYubiController.js"></script>
     <script src="app/settings/settingsSessionsController.js"></script>
diff --git a/src/less/vault.less b/src/less/vault.less
index 4697726081d..48c4ce67265 100644
--- a/src/less/vault.less
+++ b/src/less/vault.less
@@ -560,3 +560,24 @@ h1, h2, h3, h4, h5, h6 {
         background-position: -73px -88px;
     }
 }
+
+#duoFrameWrapper {
+    margin: 0 -36px 10px -36px;
+    background: ~"url('../images/loading.svg') 0 0 no-repeat";
+
+    @media (min-width: 360px) {
+        margin: 0 -10px 10px -10px;
+    }
+
+    @media (min-width: @screen-sm) {
+        margin: 0 0 10px;
+    }
+
+    iframe {
+        width: 100%;
+        min-width: 304px;
+        max-width: 620px;
+        height: 500px;
+        border: none;
+    }
+}