diff --git a/src/execution/__tests__/executor-test.ts b/src/execution/__tests__/executor-test.ts
index 5283aa4de51..b3090202580 100644
--- a/src/execution/__tests__/executor-test.ts
+++ b/src/execution/__tests__/executor-test.ts
@@ -18,7 +18,7 @@ import {
   GraphQLUnionType,
 } from '../../type/definition';
 
-import { execute, executeSync } from '../execute';
+import { Executor, execute, executeSync } from '../execute';
 
 describe('Execute: Handles basic execution tasks', () => {
   it('throws if no document is provided', () => {
@@ -1151,6 +1151,32 @@ describe('Execute: Handles basic execution tasks', () => {
     expect(result).to.deep.equal({ data: { foo: null } });
   });
 
+  it('uses a custom Executor', () => {
+    const schema = new GraphQLSchema({
+      query: new GraphQLObjectType({
+        name: 'Query',
+        fields: {
+          foo: { type: GraphQLString },
+        },
+      }),
+    });
+    const document = parse('{ foo }');
+
+    class CustomExecutor extends Executor {
+      executeField() {
+        return 'foo';
+      }
+    }
+
+    const result = executeSync({
+      schema,
+      document,
+      CustomExecutor,
+    });
+
+    expect(result).to.deep.equal({ data: { foo: 'foo' } });
+  });
+
   it('uses a custom field resolver', () => {
     const schema = new GraphQLSchema({
       query: new GraphQLObjectType({
diff --git a/src/execution/execute.ts b/src/execution/execute.ts
index 1d369a9054c..345913d8e4d 100644
--- a/src/execution/execute.ts
+++ b/src/execution/execute.ts
@@ -128,6 +128,7 @@ export interface ExecutionArgs {
   operationName?: Maybe<string>;
   fieldResolver?: Maybe<GraphQLFieldResolver<any, any>>;
   typeResolver?: Maybe<GraphQLTypeResolver<any, any>>;
+  CustomExecutor?: Maybe<typeof Executor>;
 }
 
 /**
@@ -150,6 +151,7 @@ export function execute(args: ExecutionArgs): PromiseOrValue<ExecutionResult> {
     operationName,
     fieldResolver,
     typeResolver,
+    CustomExecutor,
   } = args;
 
   // If arguments are missing or incorrect, throw an error.
@@ -173,7 +175,7 @@ export function execute(args: ExecutionArgs): PromiseOrValue<ExecutionResult> {
     return { errors: exeContext };
   }
 
-  const executor = new Executor(exeContext);
+  const executor = new (CustomExecutor ?? Executor)(exeContext);
 
   // Return a Promise that will eventually resolve to the data described by
   // The "Response" section of the GraphQL specification.
diff --git a/src/execution/index.ts b/src/execution/index.ts
index 5ae0706ec95..52c9aed00f8 100644
--- a/src/execution/index.ts
+++ b/src/execution/index.ts
@@ -1,6 +1,7 @@
 export { pathToArray as responsePathAsArray } from '../jsutils/Path';
 
 export {
+  Executor,
   execute,
   executeSync,
   defaultFieldResolver,
diff --git a/src/graphql.ts b/src/graphql.ts
index 03e6b95882e..c8cff1681a0 100644
--- a/src/graphql.ts
+++ b/src/graphql.ts
@@ -14,7 +14,7 @@ import type {
 import type { GraphQLSchema } from './type/schema';
 import { validateSchema } from './type/validate';
 
-import type { ExecutionResult } from './execution/execute';
+import type { ExecutionResult, Executor } from './execution/execute';
 import { execute } from './execution/execute';
 
 /**
@@ -55,6 +55,18 @@ import { execute } from './execution/execute';
  *    A type resolver function to use when none is provided by the schema.
  *    If not provided, the default type resolver is used (which looks for a
  *    `__typename` field or alternatively calls the `isTypeOf` method).
+ * CustomExecutor:
+ *    A custom Executor class to allow overriding execution behavior.
+ *
+ *    Note: The Executor class is exported only to assist people in
+ *    implementing their own executors without duplicating too much code and
+ *    should be used only as last resort for cases requiring custom execution
+ *    or if certain features could not be contributed upstream.
+ *
+ *    It is still part of the internal API and is versioned, so any changes to
+ *    it are never considered breaking changes. If you still need to support
+ *    multiple versions of the library, please use the `versionInfo` variable
+ *    for version detection.
  */
 export interface GraphQLArgs {
   schema: GraphQLSchema;
@@ -65,6 +77,7 @@ export interface GraphQLArgs {
   operationName?: Maybe<string>;
   fieldResolver?: Maybe<GraphQLFieldResolver<any, any>>;
   typeResolver?: Maybe<GraphQLTypeResolver<any, any>>;
+  CustomExecutor?: Maybe<typeof Executor>;
 }
 
 export function graphql(args: GraphQLArgs): Promise<ExecutionResult> {
@@ -99,6 +112,7 @@ function graphqlImpl(args: GraphQLArgs): PromiseOrValue<ExecutionResult> {
     operationName,
     fieldResolver,
     typeResolver,
+    CustomExecutor,
   } = args;
 
   // Validate Schema
@@ -131,5 +145,6 @@ function graphqlImpl(args: GraphQLArgs): PromiseOrValue<ExecutionResult> {
     operationName,
     fieldResolver,
     typeResolver,
+    CustomExecutor,
   });
 }
diff --git a/src/index.ts b/src/index.ts
index b9aec6a43ae..b2bccf4deba 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -299,6 +299,7 @@ export type {
 
 /** Execute GraphQL queries. */
 export {
+  Executor,
   execute,
   executeSync,
   defaultFieldResolver,
diff --git a/src/subscription/subscribe.ts b/src/subscription/subscribe.ts
index 3f813f4dd6c..368a14a1129 100644
--- a/src/subscription/subscribe.ts
+++ b/src/subscription/subscribe.ts
@@ -35,6 +35,7 @@ export interface SubscriptionArgs {
   operationName?: Maybe<string>;
   fieldResolver?: Maybe<GraphQLFieldResolver<any, any>>;
   subscribeFieldResolver?: Maybe<GraphQLFieldResolver<any, any>>;
+  CustomExecutor?: Maybe<typeof SubscriptionExecutor>;
 }
 
 /**
@@ -70,6 +71,7 @@ export async function subscribe(
     operationName,
     fieldResolver,
     subscribeFieldResolver,
+    CustomExecutor,
   } = args;
 
   const resultOrStream = await createSourceEventStream(
@@ -80,6 +82,7 @@ export async function subscribe(
     variableValues,
     operationName,
     subscribeFieldResolver,
+    CustomExecutor,
   );
 
   if (!isAsyncIterable(resultOrStream)) {
@@ -101,6 +104,7 @@ export async function subscribe(
       variableValues,
       operationName,
       fieldResolver,
+      CustomExecutor,
     });
 
   // Map every source value to a ExecutionResult value as described above.
@@ -143,6 +147,7 @@ export async function createSourceEventStream(
   variableValues?: Maybe<{ readonly [variable: string]: unknown }>,
   operationName?: Maybe<string>,
   fieldResolver?: Maybe<GraphQLFieldResolver<any, any>>,
+  CustomExecutor?: Maybe<typeof SubscriptionExecutor>,
 ): Promise<AsyncIterable<unknown> | ExecutionResult> {
   // If arguments are missing or incorrectly typed, this is an internal
   // developer mistake which should throw an early error.
@@ -165,7 +170,7 @@ export async function createSourceEventStream(
       return { errors: exeContext };
     }
 
-    const executor = new SubscriptionExecutor(exeContext);
+    const executor = new (CustomExecutor ?? SubscriptionExecutor)(exeContext);
 
     const eventStream = await executor.executeSubscription();