diff --git a/lib/cli/run-helpers.js b/lib/cli/run-helpers.js
index 017d914f4d..c46e0d16fe 100644
--- a/lib/cli/run-helpers.js
+++ b/lib/cli/run-helpers.js
@@ -200,11 +200,12 @@ exports.runMocha = async (mocha, options) => {
     extension = [],
     ignore = [],
     file = [],
-    parallel = false,
     recursive = false,
     sort = false,
-    spec = []
+    spec = [],
+    parallelForce = false
   } = options;
+  let {parallel} = options;
 
   const fileCollectParams = {
     ignore,
@@ -215,6 +216,14 @@ exports.runMocha = async (mocha, options) => {
     spec
   };
 
+  const files = collectFiles(fileCollectParams);
+  if (files.length === 1) {
+    if (parallel && !parallelForce) {
+      mocha.parallelMode(false);
+      parallel = false;
+    }
+  }
+
   let run;
   if (watch) {
     run = parallel ? watchParallelRun : watchRun;
diff --git a/lib/cli/run-option-metadata.js b/lib/cli/run-option-metadata.js
index 33cd15ae08..ceb9eda621 100644
--- a/lib/cli/run-option-metadata.js
+++ b/lib/cli/run-option-metadata.js
@@ -45,7 +45,8 @@ const TYPES = (exports.types = {
     'parallel',
     'recursive',
     'sort',
-    'watch'
+    'watch',
+    'parallelForce'
   ],
   number: ['retries', 'jobs'],
   string: [
diff --git a/lib/cli/run.js b/lib/cli/run.js
index 6582a4e2c5..49c2a2231c 100644
--- a/lib/cli/run.js
+++ b/lib/cli/run.js
@@ -260,6 +260,10 @@ exports.builder = yargs =>
         requiresArg: true,
         coerce: list,
         default: defaults['watch-ignore']
+      },
+      parallelForce: {
+        description: 'Force Mocha to quit after tests complete',
+        group: GROUPS.RULES
       }
     })
     .positional('spec', {
diff --git a/lib/mocha.js b/lib/mocha.js
index 350df62dbc..4bd9a874b7 100644
--- a/lib/mocha.js
+++ b/lib/mocha.js
@@ -123,6 +123,7 @@ exports.Test = require('./test');
  * @param {number|string} [options.timeout] - Timeout threshold value.
  * @param {string} [options.ui] - Interface name.
  * @param {boolean} [options.parallel] - Run jobs in parallel
+ * @param {boolean} [options.parallelForce] - Run jobs in parallel
  * @param {number} [options.jobs] - Max number of worker processes for parallel runs
  * @param {MochaRootHookObject} [options.rootHooks] - Hooks to bootstrap the root
  * suite with