diff --git a/lib/Server.js b/lib/Server.js
index 8301581d01..3185b34586 100644
--- a/lib/Server.js
+++ b/lib/Server.js
@@ -726,13 +726,21 @@ class Server {
         options.server.options.requestCert = false;
       }
 
-      // TODO remove the `cacert` option in favor `ca` in the next major release
       for (const property of ["cacert", "ca", "cert", "crl", "key", "pfx"]) {
         if (typeof options.server.options[property] === "undefined") {
           // eslint-disable-next-line no-continue
           continue;
         }
 
+        if (property === "cacert") {
+          // TODO remove the `cacert` option in favor `ca` in the next major release
+          util.deprecate(
+            () => {},
+            "The 'cacert' option is deprecated. Please use the 'ca' option.",
+            "DEP_WEBPACK_DEV_SERVER_CACERT"
+          )();
+        }
+
         const value = options.server.options[property];
         const readFile = (item) => {
           if (
diff --git a/test/e2e/https.test.js b/test/e2e/https.test.js
index 4ab76466f9..dee1a9b3c8 100644
--- a/test/e2e/https.test.js
+++ b/test/e2e/https.test.js
@@ -655,11 +655,13 @@ describe("https option", () => {
     let browser;
     let pageErrors;
     let consoleMessages;
+    let utilSpy;
 
     beforeEach(async () => {
       compiler = webpack(config);
 
       createServerSpy = jest.spyOn(https, "createServer");
+      utilSpy = jest.spyOn(util, "deprecate");
 
       server = new Server(
         {
@@ -697,6 +699,7 @@ describe("https option", () => {
 
     afterEach(async () => {
       createServerSpy.mockRestore();
+      utilSpy.mockRestore();
 
       await browser.close();
       await server.stop();
@@ -715,6 +718,9 @@ describe("https option", () => {
         waitUntil: "networkidle0",
       });
 
+      expect(utilSpy.mock.calls[1][1]).toBe(
+        "The 'cacert' option is deprecated. Please use the 'ca' option."
+      );
       expect(
         normalizeOptions(createServerSpy.mock.calls[0][0])
       ).toMatchSnapshot("https options");
diff --git a/test/e2e/server.test.js b/test/e2e/server.test.js
index 7b77e8d629..f24a46e2dd 100644
--- a/test/e2e/server.test.js
+++ b/test/e2e/server.test.js
@@ -2,6 +2,7 @@
 
 const https = require("https");
 const path = require("path");
+const util = require("util");
 const fs = require("graceful-fs");
 const request = require("supertest");
 const spdy = require("spdy");
@@ -871,11 +872,13 @@ describe("server option", () => {
       let browser;
       let pageErrors;
       let consoleMessages;
+      let utilSpy;
 
       beforeEach(async () => {
         compiler = webpack(config);
 
         createServerSpy = jest.spyOn(https, "createServer");
+        utilSpy = jest.spyOn(util, "deprecate");
 
         server = new Server(
           {
@@ -916,6 +919,7 @@ describe("server option", () => {
 
       afterEach(async () => {
         createServerSpy.mockRestore();
+        utilSpy.mockRestore();
 
         await browser.close();
         await server.stop();
@@ -934,6 +938,9 @@ describe("server option", () => {
           waitUntil: "networkidle0",
         });
 
+        expect(utilSpy.mock.calls[0][1]).toBe(
+          "The 'cacert' option is deprecated. Please use the 'ca' option."
+        );
         expect(
           normalizeOptions(createServerSpy.mock.calls[0][0])
         ).toMatchSnapshot("https options");