diff --git a/packages/arcgis-rest-common-types/src/group.ts b/packages/arcgis-rest-common-types/src/group.ts
index 22df6750f8..8eeedf2af4 100644
--- a/packages/arcgis-rest-common-types/src/group.ts
+++ b/packages/arcgis-rest-common-types/src/group.ts
@@ -42,7 +42,7 @@ export interface IGroup extends IGroupAdd {
   protected: boolean;
   isInvitationOnly: boolean;
   isViewOnly: boolean;
-  isOpenData: boolean;
+  isOpenData?: boolean;
   isFav: boolean;
   autoJoin: boolean;
   userMembership?: {
diff --git a/packages/arcgis-rest-users/src/index.ts b/packages/arcgis-rest-users/src/index.ts
index 2b19f5656f..be959a8cb5 100644
--- a/packages/arcgis-rest-users/src/index.ts
+++ b/packages/arcgis-rest-users/src/index.ts
@@ -3,3 +3,4 @@
 
 export * from "./get";
 export * from "./notification";
+export * from "./invitation";
diff --git a/packages/arcgis-rest-users/src/invitation.ts b/packages/arcgis-rest-users/src/invitation.ts
new file mode 100644
index 0000000000..7fbb33770e
--- /dev/null
+++ b/packages/arcgis-rest-users/src/invitation.ts
@@ -0,0 +1,102 @@
+/* Copyright (c) 2018 Environmental Systems Research Institute, Inc.
+ * Apache-2.0 */
+
+import { request, getPortalUrl } from "@esri/arcgis-rest-request";
+
+import { IUserRequestOptions } from "@esri/arcgis-rest-auth";
+import { IGroup } from "@esri/arcgis-rest-common-types";
+
+export interface IInvitation {
+  id: string;
+  targetType: string;
+  targetId: string;
+  received: number;
+  accepted: boolean;
+  mustApprove: boolean;
+  email: string;
+  role: string;
+  type: string;
+  dateAccepted: number;
+  expiration: number;
+  created: number;
+  username: string;
+  fromUsername: {
+    username: string;
+    fullname?: string;
+  };
+  group?: IGroup;
+  groupId?: string;
+}
+
+export interface IInvitationResult {
+  userInvitations: IInvitation[];
+}
+
+/**
+ * Get invitations for a user.
+ *
+ * @param requestOptions - options to pass through in the request
+ * @returns A Promise that will resolve with the user's invitations
+ */
+export function getUserInvitations(
+  requestOptions: IUserRequestOptions
+): Promise<IInvitationResult> {
+  let options = { httpMethod: "GET" } as IUserRequestOptions;
+
+  const username = encodeURIComponent(requestOptions.authentication.username);
+  const portalUrl = getPortalUrl(requestOptions);
+  const url = `${portalUrl}/community/users/${username}/invitations`;
+  options = { ...requestOptions, ...options };
+
+  // send the request
+  return request(url, options);
+}
+
+/**
+ * Get an invitation for a user by id.
+ *
+ * @param requestOptions - options to pass through in the request
+ * @returns A Promise that will resolve with the invitation
+ */
+export function getUserInvitation(
+  id: string,
+  requestOptions: IUserRequestOptions
+): Promise<IInvitation> {
+  let options = { httpMethod: "GET" } as IUserRequestOptions;
+
+  const username = encodeURIComponent(requestOptions.authentication.username);
+  const portalUrl = getPortalUrl(requestOptions);
+  const url = `${portalUrl}/community/users/${username}/invitations/${id}`;
+  options = { ...requestOptions, ...options };
+
+  // send the request
+  return request(url, options);
+}
+
+/**
+ * Accept an invitation.
+ *
+ * @param requestOptions - Options for the request
+ * @returns A Promise that will resolve with the success/failure status of the request
+ */
+export function acceptInvitation(
+  id: string,
+  requestOptions: IUserRequestOptions
+): Promise<any> {
+  const username = encodeURIComponent(requestOptions.authentication.username);
+  const portalUrl = getPortalUrl(requestOptions);
+  const url = `${portalUrl}/community/users/${username}/invitations/${id}/accept`;
+
+  return request(url, requestOptions);
+}
+
+export function declineInvitation(
+  id: string,
+  requestOptions: IUserRequestOptions
+): Promise<any> {
+  const username = encodeURIComponent(requestOptions.authentication.username);
+  const portalUrl = getPortalUrl(requestOptions);
+  const url = `${portalUrl}/community/users/${username}/invitations/${id}/decline`;
+
+  return request(url, requestOptions);
+}
diff --git a/packages/arcgis-rest-users/test/invitation.test.ts b/packages/arcgis-rest-users/test/invitation.test.ts
new file mode 100644
index 0000000000..a5286cc01e
--- /dev/null
+++ b/packages/arcgis-rest-users/test/invitation.test.ts
@@ -0,0 +1,169 @@
+/* Copyright (c) 2018 Environmental Systems Research Institute, Inc.
+ * Apache-2.0 */
+
+import {
+  getUserInvitations,
+  getUserInvitation,
+  acceptInvitation,
+  declineInvitation
+} from "../src/index";
+
+import {
+  UserInvitationsResponse,
+  UserInvitationResponse
+} from "./mocks/responses";
+
+import { encodeParam } from "@esri/arcgis-rest-request";
+import { UserSession } from "@esri/arcgis-rest-auth";
+import * as fetchMock from "fetch-mock";
+
+const TOMORROW = (function() {
+  const now = new Date();
+  now.setDate(now.getDate() + 1);
+  return now;
+})();
+
+describe("invitations", () => {
+  afterEach(fetchMock.restore);
+
+  const session = new UserSession({
+    username: "c@sey",
+    password: "123456",
+    portal: "https://myorg.maps.arcgis.com/sharing/rest"
+  });
+
+  fetchMock.postOnce(
+    "https://myorg.maps.arcgis.com/sharing/rest/generateToken",
+    {
+      token: "fake-token",
+      expires: TOMORROW.getTime(),
+      username: "c@sey"
+    }
+  );
+
+  describe("getUserInvitations", () => {
+    session.refreshSession();
+
+    it("should make an authenticated request for user invitations", done => {
+      fetchMock.once("*", UserInvitationsResponse);
+
+      getUserInvitations({ authentication: session })
+        .then(response => {
+          expect(fetchMock.called()).toEqual(true);
+          const [url, options]: [string, RequestInit] = fetchMock.lastCall("*");
+          expect(url).toEqual(
+            "https://myorg.maps.arcgis.com/sharing/rest/community/users/c%40sey/invitations?f=json&token=fake-token"
+          );
+          expect(options.method).toBe("GET");
+          expect(response.userInvitations.length).toEqual(1);
+          done();
+        })
+        .catch(e => {
+          fail(e);
+        });
+    });
+  });
+
+  describe("getUserInvitation", () => {
+    fetchMock.postOnce(
+      "https://myorg.maps.arcgis.com/sharing/rest/generateToken",
+      {
+        token: "fake-token",
+        expires: TOMORROW.getTime(),
+        username: "c@sey"
+      }
+    );
+
+    session.refreshSession();
+
+    it("should make an authenticated request for a user invitation", done => {
+      fetchMock.once("*", UserInvitationResponse);
+
+      getUserInvitation("3ef", { authentication: session })
+        .then(response => {
+          expect(fetchMock.called()).toEqual(true);
+          const [url, options]: [string, RequestInit] = fetchMock.lastCall("*");
+          expect(url).toEqual(
+            "https://myorg.maps.arcgis.com/sharing/rest/community/users/c%40sey/invitations/3ef?f=json&token=fake-token"
+          );
+          expect(options.method).toBe("GET");
+          expect(response.id).toEqual("G45ad52e7560e470598815499003c13f6");
+          expect(response.id).toEqual("G45ad52e7560e470598815499003c13f6");
+          done();
+        })
+        .catch(e => {
+          fail(e);
+        });
+    });
+  });
+
+  describe("acceptInvitation", () => {
+    fetchMock.postOnce(
+      "https://myorg.maps.arcgis.com/sharing/rest/generateToken",
+      {
+        token: "fake-token",
+        expires: TOMORROW.getTime(),
+        username: "c@sey"
+      }
+    );
+
+    session.refreshSession();
+
+    it("should accept an invitation", done => {
+      fetchMock.once("*", { success: true });
+
+      acceptInvitation("3ef", { authentication: session })
+        .then(response => {
+          expect(fetchMock.called()).toEqual(true);
+          const [url, options]: [string, RequestInit] = fetchMock.lastCall("*");
+          expect(url).toEqual(
+            "https://myorg.maps.arcgis.com/sharing/rest/community/users/c%40sey/invitations/3ef/accept"
+          );
+          expect(options.method).toBe("POST");
+          expect(options.body).toContain(encodeParam("f", "json"));
+          expect(options.body).toContain(encodeParam("token", "fake-token"));
+          expect(response.success).toEqual(true);
+          // expect(response.notificationId).toBe("3ef");
+          done();
+        })
+        .catch(e => {
+          fail(e);
+        });
+    });
+  });
+
+  describe("declineInvitation", () => {
+    fetchMock.postOnce(
+      "https://myorg.maps.arcgis.com/sharing/rest/generateToken",
+      {
+        token: "fake-token",
+        expires: TOMORROW.getTime(),
+        username: "c@sey"
+      }
+    );
+
+    session.refreshSession();
+
+    it("should decline an invitation", done => {
+      fetchMock.once("*", { success: true });
+
+      declineInvitation("3ef", { authentication: session })
+        .then(response => {
+          expect(fetchMock.called()).toEqual(true);
+          const [url, options]: [string, RequestInit] = fetchMock.lastCall("*");
+          expect(url).toEqual(
+            "https://myorg.maps.arcgis.com/sharing/rest/community/users/c%40sey/invitations/3ef/decline"
+          );
+          expect(options.method).toBe("POST");
+          expect(options.body).toContain(encodeParam("f", "json"));
+          expect(options.body).toContain(encodeParam("token", "fake-token"));
+          expect(response.success).toEqual(true);
+          // expect(response.notificationId).toBe("3ef");
+          done();
+        })
+        .catch(e => {
+          fail(e);
+        });
+    });
+  });
+});
diff --git a/packages/arcgis-rest-users/test/mocks/responses.ts b/packages/arcgis-rest-users/test/mocks/responses.ts
index 759e2d6bc3..cb02511047 100644
--- a/packages/arcgis-rest-users/test/mocks/responses.ts
+++ b/packages/arcgis-rest-users/test/mocks/responses.ts
@@ -3,6 +3,7 @@
 
 import { IUser } from "@esri/arcgis-rest-common-types";
 import { INotificationResult } from "../../src/notification";
+import { IInvitation, IInvitationResult } from "../../src/invitation";
 
 export const AnonUserResponse: IUser = {
   username: "jsmith",
@@ -205,3 +206,72 @@ export const IDeleteSuccessResponse: any = {
   success: true,
   notificationId: "3ef"
 };
+
+export const UserInvitationsResponse: IInvitationResult = {
+  userInvitations: [
+    {
+      id: "G45ad52e7560e470598815499003c13f6",
+      targetType: "group",
+      targetId: "5d780fcf924e4e7ab1952a71472bc950",
+      received: 1538516323000,
+      accepted: false,
+      mustApprove: false,
+      email: null,
+      role: "group_member",
+      type: "user",
+      dateAccepted: -1,
+      expiration: 1539725923000,
+      created: 1538516323000,
+      username: "mjuniper_dcqa",
+      fromUsername: {
+        username: "dcadminqa"
+      },
+      groupId: "5d780fcf924e4e7ab1952a71472bc950"
+    }
+  ]
+};
+
+export const UserInvitationResponse: IInvitation = {
+  id: "G45ad52e7560e470598815499003c13f6",
+  targetType: "group",
+  targetId: "5d780fcf924e4e7ab1952a71472bc950",
+  received: 1538516323000,
+  accepted: false,
+  mustApprove: false,
+  email: null,
+  role: "group_member",
+  type: "user",
+  dateAccepted: -1,
+  expiration: 1539725923000,
+  created: 1538516323000,
+  username: "mjuniper_dcqa",
+  fromUsername: {
+    username: "dcadminqa",
+    fullname: "DcAdminQA QaExtDc"
+  },
+  group: {
+    id: "5d780fcf924e4e7ab1952a71472bc950",
+    title: "Jupe test group 2",
+    isInvitationOnly: true,
+    owner: "dcadminqa",
+    description: null,
+    snippet: null,
+    tags: ["hub"],
+    phone: null,
+    sortField: "title",
+    sortOrder: "asc",
+    isViewOnly: false,
+    thumbnail: null,
+    created: 1538516296000,
+    modified: 1538516296000,
+    access: "public",
+    capabilities: [],
+    isFav: false,
+    isReadOnly: false,
+    protected: false,
+    autoJoin: false,
+    notificationsEnabled: false,
+    provider: null,
+    providerGroupName: null
+  }
+};