diff --git a/.mocharc.js b/.mocharc.js
new file mode 100644
index 000000000..44fd10405
--- /dev/null
+++ b/.mocharc.js
@@ -0,0 +1,12 @@
+// Force mocha to exit after the test run completes.
+//
+// mocha 3 exited automatically when tests finished. mocha 4+ waits for the
+// event loop to drain, so a test that leaks a handle (an open socket, a timer,
+// a server still listening) keeps the process alive. In CI this makes the run
+// reach the VM wall-clock cap and get killed, even though all tests passed.
+//
+// mocha searches upward for the nearest rc file, so this single root config
+// applies to every package's `gulp test` task.
+module.exports = {
+  exit: true,
+};
diff --git a/package.json b/package.json
index a5733f377..a5c9e4797 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
   "devDependencies": {
     "@types/execa": "^0.8.0",
     "@types/gulp": "^4.0.5",
-    "@types/gulp-mocha": "0.0.31",
+    "@types/gulp-mocha": "0.0.37",
     "@types/ncp": "^2.0.1",
     "@types/node": "^8.0.32",
     "@types/pify": "^3.0.0",
@@ -21,7 +21,7 @@
     "execa": "^0.8.0",
     "gulp": "^4.0.1",
     "gulp-jshint": "^2.0.4",
-    "gulp-mocha": "^4.3.1",
+    "gulp-mocha": "9.0.0",
     "gulp-sourcemaps": "^2.6.1",
     "gulp-tslint": "^8.1.1",
     "gulp-typescript": "^3.2.2",
@@ -30,8 +30,8 @@
     "jshint": "^2.9.5",
     "make-dir": "^1.1.0",
     "merge2": "^1.1.0",
-    "mocha": "^3.5.3",
-    "mocha-jenkins-reporter": "^0.3.9",
+    "mocha": "^10.8.2",
+    "mocha-jenkins-reporter": "^0.4.8",
     "ncp": "^2.0.0",
     "nyc": "^11.7.2",
     "pify": "^3.0.0",
@@ -59,6 +59,14 @@
     "cache": true,
     "all": true
   },
+  "overrides": {
+    "mocha": {
+      "serialize-javascript": "^7.0.5"
+    },
+    "mocha-jenkins-reporter": {
+      "diff": "^4.0.4"
+    }
+  },
   "scripts": {
     "test": "nyc gulp test",
     "coverage": "nyc report --reporter=text-lcov | coveralls"
diff --git a/test/client-libraries-integration/package.json b/test/client-libraries-integration/package.json
index 784714eeb..b70101dd8 100644
--- a/test/client-libraries-integration/package.json
+++ b/test/client-libraries-integration/package.json
@@ -5,7 +5,7 @@
   "dependencies": {
     "dot-prop": "^5.2.0",
     "google-proto-files": "^0.15.1",
-    "mocha": "^5.0.4",
+    "mocha": "^10.8.2",
     "shimmer": "^1.2.0"
   }
 }