diff --git a/README.md b/README.md
index a7e5a8dc..5dc851ba 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,7 @@ A _Good Enough_ offline emulator for [Amazon Cognito](https://aws.amazon.com/cog
 - [ForgotPassword](https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_ForgotPassword.html)
 - [GetUser](https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_GetUser.html)
 - [InitiateAuth](https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_InitiateAuth.html)
+- [ListGroups](https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_ListGroups.html)
 - [ListUsers](https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_ListUsers.html)
 - [RespondToAuthChallenge](https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_RespondToAuthChallenge.html)
 - [SignUp](https://docs.aws.amazon.com/cognito-user-identity-pools/latest/APIReference/API_SignUp.html)
diff --git a/integration-tests/aws-sdk/listGroups.test.ts b/integration-tests/aws-sdk/listGroups.test.ts
new file mode 100644
index 00000000..dfa37116
--- /dev/null
+++ b/integration-tests/aws-sdk/listGroups.test.ts
@@ -0,0 +1,98 @@
+import { ClockFake } from "../../src/__tests__/clockFake";
+import { withCognitoSdk } from "./setup";
+
+const originalDate = new Date();
+const roundedDate = new Date(originalDate.getTime());
+roundedDate.setMilliseconds(0);
+
+const clock = new ClockFake(originalDate);
+
+describe(
+  "CognitoIdentityServiceProvider.listGroups",
+  withCognitoSdk(
+    (Cognito) => {
+      it("lists groups", async () => {
+        const client = Cognito();
+
+        await client
+          .createGroup({
+            GroupName: "abc",
+            UserPoolId: "test1",
+          })
+          .promise();
+        await client
+          .createGroup({
+            GroupName: "def",
+            UserPoolId: "test1",
+          })
+          .promise();
+        await client
+          .createGroup({
+            GroupName: "ghi",
+            UserPoolId: "test2",
+          })
+          .promise();
+
+        const result1 = await client
+          .listGroups({
+            UserPoolId: "test1",
+          })
+          .promise();
+
+        expect(result1).toEqual({
+          Groups: [
+            {
+              CreationDate: roundedDate,
+              GroupName: "abc",
+              LastModifiedDate: roundedDate,
+              UserPoolId: "test1",
+            },
+            {
+              CreationDate: roundedDate,
+              GroupName: "def",
+              LastModifiedDate: roundedDate,
+              UserPoolId: "test1",
+            },
+          ],
+        });
+
+        const result2 = await client
+          .listGroups({
+            UserPoolId: "test2",
+          })
+          .promise();
+
+        expect(result2).toEqual({
+          Groups: [
+            {
+              CreationDate: roundedDate,
+              GroupName: "ghi",
+              LastModifiedDate: roundedDate,
+              UserPoolId: "test2",
+            },
+          ],
+        });
+      });
+
+      it("returns an empty collection when there are no groups", async () => {
+        const client = Cognito();
+
+        const result = await client
+          .listGroups({
+            UserPoolId: "test1",
+          })
+          .promise();
+
+        expect(result).toEqual({
+          Groups: [],
+        });
+      });
+
+      // TODO: getUserPool lazily creates a pool right now, so we can't handle invalid user pools
+      it.todo("handles invalid user pool");
+    },
+    {
+      clock,
+    }
+  )
+);
diff --git a/src/targets/listGroups.test.ts b/src/targets/listGroups.test.ts
new file mode 100644
index 00000000..daba1f6c
--- /dev/null
+++ b/src/targets/listGroups.test.ts
@@ -0,0 +1,67 @@
+import { MockUserPoolClient } from "../__tests__/mockUserPoolClient";
+import { CognitoClient } from "../services";
+import { ListGroups, ListGroupsTarget } from "./listGroups";
+
+describe("ListGroups target", () => {
+  let listGroups: ListGroupsTarget;
+  let mockCognitoClient: jest.Mocked<CognitoClient>;
+  let now: Date;
+
+  beforeEach(() => {
+    now = new Date(2020, 1, 2, 3, 4, 5);
+
+    mockCognitoClient = {
+      getAppClient: jest.fn(),
+      getUserPool: jest.fn().mockResolvedValue(MockUserPoolClient),
+      getUserPoolForClientId: jest.fn().mockResolvedValue(MockUserPoolClient),
+    };
+
+    listGroups = ListGroups({
+      cognitoClient: mockCognitoClient,
+    });
+  });
+
+  it("lists groups", async () => {
+    MockUserPoolClient.listGroups.mockResolvedValue([
+      {
+        CreationDate: now.getTime(),
+        Description: "Description",
+        GroupName: "abc",
+        LastModifiedDate: now.getTime(),
+        Precedence: 1,
+        RoleArn: "ARN",
+      },
+      {
+        CreationDate: now.getTime(),
+        GroupName: "def",
+        LastModifiedDate: now.getTime(),
+      },
+    ]);
+
+    const output = await listGroups({
+      UserPoolId: "userPoolId",
+    });
+
+    expect(output).toBeDefined();
+    expect(output.Groups).toEqual([
+      {
+        CreationDate: now,
+        Description: "Description",
+        GroupName: "abc",
+        LastModifiedDate: now,
+        Precedence: 1,
+        RoleArn: "ARN",
+        UserPoolId: "userPoolId",
+      },
+      {
+        CreationDate: now,
+        GroupName: "def",
+        LastModifiedDate: now,
+        UserPoolId: "userPoolId",
+      },
+    ]);
+  });
+
+  it.todo("supports Limit to specify the number of groups to return");
+  it.todo("supports PaginationToken to paginate results");
+});
diff --git a/src/targets/listGroups.ts b/src/targets/listGroups.ts
new file mode 100644
index 00000000..4dbfbf2d
--- /dev/null
+++ b/src/targets/listGroups.ts
@@ -0,0 +1,33 @@
+import {
+  ListGroupsRequest,
+  ListGroupsResponse,
+} from "aws-sdk/clients/cognitoidentityserviceprovider";
+import { Services } from "../services";
+
+export type ListGroupsTarget = (
+  req: ListGroupsRequest
+) => Promise<ListGroupsResponse>;
+
+type ListGroupServices = Pick<Services, "cognitoClient">;
+
+export const ListGroups = ({
+  cognitoClient,
+}: ListGroupServices): ListGroupsTarget => async (req) => {
+  // TODO: Limit support
+  // TODO: PaginationToken support
+
+  const userPool = await cognitoClient.getUserPool(req.UserPoolId);
+  const groups = await userPool.listGroups();
+
+  return {
+    Groups: groups.map((group) => ({
+      CreationDate: new Date(group.CreationDate),
+      Description: group.Description,
+      GroupName: group.GroupName,
+      LastModifiedDate: new Date(group.LastModifiedDate),
+      Precedence: group.Precedence,
+      RoleArn: group.RoleArn,
+      UserPoolId: req.UserPoolId,
+    })),
+  };
+};
diff --git a/src/targets/router.ts b/src/targets/router.ts
index ed25520f..7ba326f5 100644
--- a/src/targets/router.ts
+++ b/src/targets/router.ts
@@ -9,6 +9,7 @@ import { DescribeUserPoolClient } from "./describeUserPoolClient";
 import { ForgotPassword } from "./forgotPassword";
 import { ChangePassword } from "./changePassword";
 import { InitiateAuth } from "./initiateAuth";
+import { ListGroups } from "./listGroups";
 import { ListUsers } from "./listUsers";
 import { RespondToAuthChallenge } from "./respondToAuthChallenge";
 import { SignUp } from "./signUp";
@@ -34,6 +35,7 @@ export const Targets = {
   ForgotPassword,
   GetUser,
   InitiateAuth,
+  ListGroups,
   ListUsers,
   RespondToAuthChallenge,
   SignUp,