diff --git a/doc/api/cli.md b/doc/api/cli.md
index 63a8d4e9057570..a2861024659af2 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -1108,14 +1108,6 @@ Starts the Node.js command line test runner. This flag cannot be combined with
 `--check`, `--eval`, `--interactive`, or the inspector. See the documentation
 on [running tests from the command line][] for more details.
 
-### `--test-concurrency`
-
-<!-- YAML
-added: REPLACEME
--->
-
-Configures the tests to run concurrently.
-
 ### `--test-only`
 
 <!-- YAML
diff --git a/lib/internal/test_runner/test.js b/lib/internal/test_runner/test.js
index 2e5b1942e7b966..ae1f76469a83ce 100644
--- a/lib/internal/test_runner/test.js
+++ b/lib/internal/test_runner/test.js
@@ -1,16 +1,15 @@
 'use strict';
 const {
   ArrayPrototypePush,
-  ArrayPrototypeReduce,
   ArrayPrototypeShift,
   ArrayPrototypeUnshift,
   FunctionPrototype,
   Number,
-  PromiseResolve,
   ReflectApply,
   SafeMap,
   PromiseRace,
   SafePromiseAll,
+  MathMax
 } = primordials;
 const { AsyncResource } = require('async_hooks');
 const {
@@ -43,9 +42,7 @@ const noop = FunctionPrototype;
 const isTestRunner = getOptionValue('--test');
 const testOnlyFlag = !isTestRunner && getOptionValue('--test-only');
 // TODO(cjihrig): Use uv_available_parallelism() once it lands.
-const isConcurrent = getOptionValue('--test-concurrency');
-const rootConcurrency = isTestRunner && isConcurrent ? cpus().length - 1 : 1;
-const subTestConcurrency = isConcurrent;
+const rootConcurrency = isTestRunner ? MathMax(cpus().length - 1, 1) : 1;
 
 function testTimeout(promise, timeout) {
   if (timeout === kDefaultTimeout) {
@@ -139,6 +136,14 @@ class Test extends AsyncResource {
       this.concurrency = concurrency;
     }
 
+    if (typeof concurrency === 'boolean') {
+      if (isTestRunner) {
+        this.concurrency = concurrency ? MathMax(cpus().length - 1, 1) : 1;
+      } else {
+        this.concurrency = concurrency ? Infinity : 1;
+      }
+    }
+
     if (isUint32(timeout)) {
       this.timeout = timeout;
     }
@@ -508,14 +513,7 @@ class Suite extends Test {
     this.parent.activeSubtests++;
     this.startTime = hrtime();
     const subtests = this.skipped || this.error ? [] : this.subtests;
-    if (subTestConcurrency) {
-      await SafePromiseAll(subtests, (subtests) => subtests.start());
-    } else {
-      await testTimeout(ArrayPrototypeReduce(subtests, async (prev, subtest) => {
-        await prev;
-        await subtest.run();
-      }, PromiseResolve()), this.timeout);
-    }
+    await SafePromiseAll(subtests, (subtests) => subtests.start());
     this.pass();
     this.postRun();
   }
diff --git a/src/node_options.cc b/src/node_options.cc
index 75971dfc0aa3d7..25e4caf98ad210 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -525,9 +525,6 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption("--test",
             "launch test runner on startup",
             &EnvironmentOptions::test_runner);
-  AddOption("--test-concurrency",
-            "tests defined within a file run in parallel",
-            &EnvironmentOptions::test_concurrency);
   AddOption("--test-only",
             "run tests with 'only' option set",
             &EnvironmentOptions::test_only,
diff --git a/src/node_options.h b/src/node_options.h
index f525bd1ecbad7e..a4744fb9e5b8a5 100644
--- a/src/node_options.h
+++ b/src/node_options.h
@@ -150,7 +150,6 @@ class EnvironmentOptions : public Options {
   std::string redirect_warnings;
   std::string diagnostic_dir;
   bool test_runner = false;
-  bool test_concurrency = false;
   bool test_only = false;
   bool test_udp_no_try_send = false;
   bool throw_deprecation = false;