diff --git a/modules/.submodules.json b/modules/.submodules.json
index f321e075208..097fe4b1f3b 100644
--- a/modules/.submodules.json
+++ b/modules/.submodules.json
@@ -1,7 +1,8 @@
 {
   "userId": [
     "digiTrustIdSystem",
-    "id5IdSystem"
+    "id5IdSystem",
+    "criteortusIdSystem"
   ],
   "adpod": [
     "freeWheelAdserverVideo"
diff --git a/modules/appnexusBidAdapter.js b/modules/appnexusBidAdapter.js
index 50c5a0e6f04..67388848815 100644
--- a/modules/appnexusBidAdapter.js
+++ b/modules/appnexusBidAdapter.js
@@ -169,6 +169,16 @@ export const spec = {
       });
     }
 
+    const rtusId = utils.deepAccess(bidRequests[0], `userId.criteortus.${BIDDER_CODE}.userid`);
+    if (rtusId) {
+      let tpuids = [];
+      tpuids.push({
+        'provider': 'criteo',
+        'user_id': rtusId
+      });
+      payload.tpuids = tpuids;
+    }
+
     const request = formatRequest(payload, bidderRequest);
     return request;
   },
diff --git a/modules/criteortusIdSystem.js b/modules/criteortusIdSystem.js
new file mode 100644
index 00000000000..02edf0ef06e
--- /dev/null
+++ b/modules/criteortusIdSystem.js
@@ -0,0 +1,105 @@
+/**
+ * This module adds Criteo Real Time User Sync to the User ID module
+ * The {@link module:modules/userId} module is required
+ * @module modules/criteortusIdSystem
+ * @requires module:modules/userId
+ */
+
+import * as utils from '../src/utils'
+import { ajax } from '../src/ajax';
+import { submodule } from '../src/hook';
+
+const key = '__pbjs_criteo_rtus';
+
+/** @type {Submodule} */
+export const criteortusIdSubmodule = {
+  /**
+   * used to link submodule with config
+   * @type {string}
+   */
+  name: 'criteortus',
+  /**
+   * decode the stored id value for passing to bid requests
+   * @function
+   * @returns {{criteortus:Object}}
+   */
+  decode() {
+    let uid = utils.getCookie(key);
+    try {
+      uid = JSON.parse(uid);
+      return { 'criteortus': uid };
+    } catch (error) {
+      utils.logError('Error in parsing criteo rtus data', error);
+    }
+  },
+  /**
+   * performs action to obtain id and return a value in the callback's response argument
+   * @function
+   * @param {SubmoduleParams} [configParams]
+   * @returns {function(callback:function)}
+   */
+  getId(configParams) {
+    if (!configParams || !utils.isPlainObject(configParams.clientIdentifier)) {
+      utils.logError('User ID - Criteo rtus requires client identifier to be defined');
+      return;
+    }
+
+    let uid = utils.getCookie(key);
+    if (uid) {
+      return uid;
+    } else {
+      let userIds = {};
+      return function(callback) {
+        let bidders = Object.keys(configParams.clientIdentifier);
+
+        function afterAllResponses() {
+          // criteo rtus user id expires in 1 hour
+          const expiresStr = (new Date(Date.now() + (60 * 60 * 1000))).toUTCString();
+          utils.setCookie(key, JSON.stringify(userIds), expiresStr);
+          callback(userIds);
+        }
+
+        const onResponse = utils.delayExecution(afterAllResponses, bidders.length);
+
+        bidders.forEach((bidder) => {
+          let url = `https://gum.criteo.com/sync?c=${configParams.clientIdentifier[bidder]}&r=3`;
+          const getSuccessHandler = (bidder) => {
+            return function onSuccess(response) {
+              if (response) {
+                try {
+                  response = JSON.parse(response);
+                  userIds[bidder] = response;
+                  onResponse();
+                } catch (error) {
+                  utils.logError(error);
+                }
+              }
+            }
+          }
+
+          const getFailureHandler = (bidder) => {
+            return function onFailure(error) {
+              utils.logError(`Criteo RTUS server call failed for ${bidder}`, error);
+              onResponse();
+            }
+          }
+
+          ajax(
+            url,
+            {
+              success: getSuccessHandler(bidder),
+              error: getFailureHandler(bidder)
+            },
+            undefined,
+            Object.assign({
+              method: 'GET',
+              withCredentials: true
+            })
+          );
+        })
+      }
+    }
+  }
+};
+
+submodule('userId', criteortusIdSubmodule);
diff --git a/modules/userId/index.js b/modules/userId/index.js
index 2091a6a763a..e83258a4e02 100644
--- a/modules/userId/index.js
+++ b/modules/userId/index.js
@@ -186,7 +186,9 @@ function processSubmoduleCallbacks(submodules) {
       submodule.callback = undefined;
       // if valid, id data should be saved to cookie/html storage
       if (idObj) {
-        setStoredValue(submodule.config.storage, idObj, submodule.config.storage.expires);
+        if (submodule.config.storage) {
+          setStoredValue(submodule.config.storage, idObj, submodule.config.storage.expires);
+        }
         // cache decoded value (this is copied to every adUnit bid)
         submodule.idObj = submodule.submodule.decode(idObj);
       } else {
@@ -299,6 +301,13 @@ function initSubmodules(submodules, consentData) {
     } else if (submodule.config.value) {
       // cache decoded value (this is copied to every adUnit bid)
       submodule.idObj = submodule.config.value;
+    } else {
+      const result = submodule.submodule.getId(submodule.config.params, consentData);
+      if (typeof result === 'function') {
+        submodule.callback = result;
+      } else {
+        submodule.idObj = submodule.submodule.decode();
+      }
     }
     carry.push(submodule);
     return carry;
@@ -332,6 +341,8 @@ function getValidSubmoduleConfigs(configRegistry, submoduleRegistry, activeStora
       carry.push(config);
     } else if (utils.isPlainObject(config.value)) {
       carry.push(config);
+    } else if (!config.storage && !config.value) {
+      carry.push(config);
     }
     return carry;
   }, []);
diff --git a/test/spec/modules/appnexusBidAdapter_spec.js b/test/spec/modules/appnexusBidAdapter_spec.js
index e55e3e32029..30d2dc08159 100644
--- a/test/spec/modules/appnexusBidAdapter_spec.js
+++ b/test/spec/modules/appnexusBidAdapter_spec.js
@@ -614,6 +614,22 @@ describe('AppNexusAdapter', function () {
         rd_stk: bidderRequest.refererInfo.stack.map((url) => encodeURIComponent(url)).join(',')
       });
     });
+
+    it('should populate tpids array when userId is available', function () {
+      const bidRequest = Object.assign({}, bidRequests[0], {
+        userId: {
+          criteortus: {
+            appnexus: {
+              userid: 'sample-userid'
+            }
+          }
+        }
+      });
+
+      const request = spec.buildRequests([bidRequest]);
+      const payload = JSON.parse(request.data);
+      expect(payload.tpuids).to.deep.equal([{provider: 'criteo', user_id: 'sample-userid'}]);
+    });
   })
 
   describe('interpretResponse', function () {
diff --git a/test/spec/modules/criteortusIdSystem_spec.js b/test/spec/modules/criteortusIdSystem_spec.js
new file mode 100644
index 00000000000..578f14d066d
--- /dev/null
+++ b/test/spec/modules/criteortusIdSystem_spec.js
@@ -0,0 +1,88 @@
+import { criteortusIdSubmodule } from 'modules/criteortusIdSystem';
+import * as utils from 'src/utils';
+
+describe('Criteo RTUS', function() {
+  let xhr;
+  let requests;
+  let getCookieStub;
+  let logErrorStub;
+
+  beforeEach(function () {
+    xhr = sinon.useFakeXMLHttpRequest();
+    requests = [];
+    xhr.onCreate = request => requests.push(request);
+    getCookieStub = sinon.stub(utils, 'getCookie');
+    logErrorStub = sinon.stub(utils, 'logError');
+  });
+
+  afterEach(function () {
+    xhr.restore();
+    getCookieStub.restore();
+    logErrorStub.restore();
+  });
+
+  it('should log error when configParams are not passed', function() {
+    criteortusIdSubmodule.getId();
+    expect(logErrorStub.calledOnce).to.be.true;
+  })
+
+  it('should call criteo endpoint to get user id', function() {
+    getCookieStub.returns(null);
+    let configParams = {
+      clientIdentifier: {
+        'sampleBidder': 1
+      }
+    }
+
+    let response = { 'status': 'ok', 'userid': 'sample-userid' }
+    let callBackSpy = sinon.spy();
+    let submoduleCallback = criteortusIdSubmodule.getId(configParams);
+    submoduleCallback(callBackSpy);
+    requests[0].respond(
+      200,
+      { 'Content-Type': 'text/plain' },
+      JSON.stringify(response)
+    );
+    expect(callBackSpy.calledOnce).to.be.true;
+    expect(callBackSpy.calledWith({'sampleBidder': response})).to.be.true;
+  })
+
+  it('should get uid from cookie and not call endpoint', function() {
+    let response = {'appnexus': {'status': 'ok', 'userid': 'sample-userid'}}
+    getCookieStub.returns(JSON.stringify(response));
+    let configParams = {
+      clientIdentifier: {
+        'sampleBidder': 1
+      }
+    }
+    let uid = criteortusIdSubmodule.getId(configParams);
+    expect(requests.length).to.equal(0);
+  })
+
+  it('should call criteo endpoint for multiple bidders', function() {
+    getCookieStub.returns(null);
+    let configParams = {
+      clientIdentifier: {
+        'sampleBidder': 1,
+        'sampleBidder2': 2
+      }
+    }
+
+    let response = { 'status': 'ok', 'userid': 'sample-userid' }
+    let callBackSpy = sinon.spy();
+    let submoduleCallback = criteortusIdSubmodule.getId(configParams);
+    submoduleCallback(callBackSpy);
+    requests[0].respond(
+      200,
+      { 'Content-Type': 'text/plain' },
+      JSON.stringify(response)
+    );
+    expect(callBackSpy.calledOnce).to.be.false;
+    requests[1].respond(
+      200,
+      { 'Content-Type': 'text/plain' },
+      JSON.stringify(response)
+    );
+    expect(callBackSpy.calledOnce).to.be.true;
+  })
+});