diff --git a/src/emulator/apphosting/serve.spec.ts b/src/emulator/apphosting/serve.spec.ts
index 819c080b3f1..8a94a461ebe 100644
--- a/src/emulator/apphosting/serve.spec.ts
+++ b/src/emulator/apphosting/serve.spec.ts
@@ -8,6 +8,8 @@ import * as utils from "./developmentServer";
 import * as configsImport from "./config";
 import * as projectPathImport from "../../projectPath";
 import { AppHostingYamlConfig } from "../../apphosting/yaml";
+import * as emulatorRegistry from "../registry";
+import * as emulatorEnvs from "../env";
 
 describe("serve", () => {
   let checkListenableStub: sinon.SinonStub;
@@ -16,6 +18,8 @@ describe("serve", () => {
   let detectStartCommandStub: sinon.SinonStub;
   let configsStub: sinon.SinonStubbedInstance<typeof configsImport>;
   let resolveProjectPathStub: sinon.SinonStub;
+  let listRunningWithInfoStub: sinon.SinonStub;
+  let setEnvVarsForEmulatorsStub: sinon.SinonStub;
 
   beforeEach(() => {
     checkListenableStub = sinon.stub(portUtils, "checkListenable");
@@ -25,6 +29,9 @@ describe("serve", () => {
     configsStub = sinon.stub(configsImport);
     resolveProjectPathStub = sinon.stub(projectPathImport, "resolveProjectPath");
 
+    listRunningWithInfoStub = sinon.stub(emulatorRegistry.EmulatorRegistry, "listRunningWithInfo");
+    setEnvVarsForEmulatorsStub = sinon.stub(emulatorEnvs, "setEnvVarsForEmulators");
+
     resolveProjectPathStub.returns("");
     detectStartCommandStub.returns("npm run dev");
   });
@@ -37,6 +44,10 @@ describe("serve", () => {
   });
 
   describe("start", () => {
+    beforeEach(() => {
+      listRunningWithInfoStub.returns([]);
+    });
+
     it("should use user-provided port if one is defined", async () => {
       checkListenableStub.onFirstCall().returns(true);
       configsStub.getLocalAppHostingConfiguration.returns(
@@ -71,4 +82,13 @@ describe("serve", () => {
       expect(spawnWithCommandStringStub.getCall(0).args[0]).to.eq(startCommand);
     });
   });
+
+  describe("getEmulatorEnvs", () => {
+    it("should omit apphosting emulator", () => {
+      listRunningWithInfoStub.returns([{ name: "apphosting" }, { name: "functions" }]);
+      serve.getEmulatorEnvs();
+
+      expect(setEnvVarsForEmulatorsStub).to.be.calledWith({}, [{ name: "functions" }]);
+    });
+  });
 });
diff --git a/src/emulator/apphosting/serve.ts b/src/emulator/apphosting/serve.ts
index 3e31a0dcdf3..cc8760a8747 100644
--- a/src/emulator/apphosting/serve.ts
+++ b/src/emulator/apphosting/serve.ts
@@ -85,9 +85,14 @@ function availablePort(host: string, port: number): Promise<boolean> {
   });
 }
 
-function getEmulatorEnvs(): Record<string, string> {
+/**
+ * Exported for unit tests
+ */
+export function getEmulatorEnvs(): Record<string, string> {
   const envs: Record<string, string> = {};
-  const emulatorInfos = EmulatorRegistry.listRunningWithInfo();
+  const emulatorInfos = EmulatorRegistry.listRunningWithInfo().filter(
+    (emulator) => emulator.name !== Emulators.APPHOSTING, // No need to set envs for the apphosting emulator itself.
+  );
   setEnvVarsForEmulators(envs, emulatorInfos);
 
   return envs;