diff --git a/src/lib/types.ts b/src/lib/types.ts
index 90b5aad..70a9bc3 100644
--- a/src/lib/types.ts
+++ b/src/lib/types.ts
@@ -4,6 +4,7 @@ import { DeferredPromise } from "@open-draft/deferred-promise";
 export type Modifier = "is" | "isNot" | "some" | "none" | "every";
 export type LogicalOperator = "AND" | "OR" | "NOT";
 
+export type MissingPrismaAction = "groupBy";
 export type NestedQueryAction = "where";
 export type NestedReadAction = "include" | "select";
 export type NestedWriteAction =
@@ -20,6 +21,7 @@ export type NestedWriteAction =
 
 export type NestedAction =
   | Prisma.PrismaAction
+  | MissingPrismaAction
   | NestedWriteAction
   | NestedReadAction
   | NestedQueryAction;
diff --git a/test/e2e/smoke.test.ts b/test/e2e/smoke.test.ts
index 68a623c..f9f942e 100644
--- a/test/e2e/smoke.test.ts
+++ b/test/e2e/smoke.test.ts
@@ -10,9 +10,6 @@ describe("smoke", () => {
   let secondUser: User;
   let post: Post;
 
-  beforeAll(() => {
-    testClient = new PrismaClient();
-  });
   beforeEach(async () => {
     firstUser = await client.user.create({
       data: {
@@ -70,6 +67,7 @@ describe("smoke", () => {
 
   describe("vanilla", () => {
     beforeAll(() => {
+      testClient = new PrismaClient();
       testClient.$use(
         createNestedMiddleware((params, next) => {
           return next(params);
@@ -153,4 +151,33 @@ describe("smoke", () => {
       expect(profile!.meta).toBe(null);
     });
   });
+
+  describe('groupBy', () => {
+    beforeAll(() => {
+      testClient = new PrismaClient();
+      testClient.$use(
+        createNestedMiddleware((params, next) => {
+          if (params.action !== 'groupBy') {
+            throw new Error('expected groupBy action')
+          }
+          return next(params);
+        })
+      );
+    });
+
+    it('calls middleware with groupBy action', async () => {
+      await expect(testClient.comment.findMany()).rejects.toThrowError(
+        'expected groupBy action'
+      );
+
+      const groupBy = await testClient.comment.groupBy({
+        by: ['authorId'],
+        orderBy: {
+          authorId: 'asc',
+        },
+      });
+
+      expect(groupBy).toHaveLength(1);
+    });
+  });
 });
diff --git a/test/unit/calls.test.ts b/test/unit/calls.test.ts
index 9b91210..df91710 100644
--- a/test/unit/calls.test.ts
+++ b/test/unit/calls.test.ts
@@ -23,7 +23,8 @@ type MiddlewareCall<Model extends Prisma.ModelName> = {
     | "findMany"
     | "include"
     | "select"
-    | "where";
+    | "where"
+    | "groupBy";
   argsPath: string;
   scope?: MiddlewareCall<any>;
   relations: {
@@ -100,6 +101,13 @@ describe("calls", () => {
       description: "aggregate",
       rootParams: createParams("User", "aggregate", {}),
     },
+    {
+      description: "groupBy",
+      rootParams: createParams("User", "groupBy", {
+        by: ["email"],
+        orderBy: { email: "asc" },
+      })
+    },
     {
       description: "nested create in create",
       rootParams: createParams("User", "create", {
@@ -4048,6 +4056,32 @@ describe("calls", () => {
         },
       ],
     },
+    {
+      description: "where in groupBy",
+      rootParams: createParams("User", "groupBy", {
+        by: ["id"],
+        orderBy: { id: "asc" },
+        where: {
+          posts: {
+            some: {
+              title: "foo",
+            },
+          },
+        },
+      }),
+      nestedCalls: [
+        {
+          action: "where",
+          model: "Post",
+          argsPath: "args.where.posts.some",
+          modifier: "some",
+          relations: {
+            to: getModelRelation("User", "posts"),
+            from: getModelRelation("Post", "author"),
+          },
+        },
+      ],
+    },
     {
       description: "correct relations for relations between same model",
       rootParams: createParams("Comment", "findMany", {
diff --git a/test/unit/helpers/createParams.ts b/test/unit/helpers/createParams.ts
index 562198c..8352bf3 100644
--- a/test/unit/helpers/createParams.ts
+++ b/test/unit/helpers/createParams.ts
@@ -64,6 +64,8 @@ type ArgsByAction<
   ? Parameters<DelegateByModel<Model>["count"]>[0]
   : Action extends "aggregate"
   ? Parameters<DelegateByModel<Model>["aggregate"]>[0]
+  : Action extends "groupBy"
+  ? Parameters<DelegateByModel<Model>["groupBy"]>[0]
   : Action extends "connectOrCreate"
   ? {
       where: Parameters<DelegateByModel<Model>["findUnique"]>[0];