diff --git a/django/test/runner.py b/django/test/runner.py
index 8ce7ac718b..71bee37297 100644
--- a/django/test/runner.py
+++ b/django/test/runner.py
@@ -404,8 +404,8 @@ class ParallelTestSuite(unittest.TestSuite):
     run_subsuite = _run_subsuite
     runner_class = RemoteTestRunner
 
-    def __init__(self, suite, processes, failfast=False, buffer=False):
-        self.subsuites = partition_suite_by_case(suite)
+    def __init__(self, subsuites, processes, failfast=False, buffer=False):
+        self.subsuites = subsuites
         self.processes = processes
         self.failfast = failfast
         self.buffer = buffer
@@ -685,22 +685,17 @@ class DiscoverRunner:
         suite = self.test_suite(all_tests)
 
         if self.parallel > 1:
-            parallel_suite = self.parallel_test_suite(
-                suite,
-                self.parallel,
-                self.failfast,
-                self.buffer,
-            )
-
+            subsuites = partition_suite_by_case(suite)
             # Since tests are distributed across processes on a per-TestCase
             # basis, there's no need for more processes than TestCases.
-            parallel_units = len(parallel_suite.subsuites)
-            self.parallel = min(self.parallel, parallel_units)
-
-            # If there's only one TestCase, parallelization isn't needed.
-            if self.parallel > 1:
-                suite = parallel_suite
-
+            processes = min(self.parallel, len(subsuites))
+            if processes > 1:
+                suite = self.parallel_test_suite(
+                    subsuites,
+                    processes,
+                    self.failfast,
+                    self.buffer,
+                )
         return suite
 
     def setup_databases(self, **kwargs):
diff --git a/tests/test_runner/test_discover_runner.py b/tests/test_runner/test_discover_runner.py
index 4eff76c5fd..3f840ee049 100644
--- a/tests/test_runner/test_discover_runner.py
+++ b/tests/test_runner/test_discover_runner.py
@@ -348,6 +348,12 @@ class DiscoverRunnerTests(SimpleTestCase):
         with self.assertRaisesMessage(ValueError, msg):
             DiscoverRunner(pdb=True, parallel=2)
 
+    def test_number_of_parallel_workers(self):
+        """Number of processes doesn't exceed the number of TestCases."""
+        runner = DiscoverRunner(parallel=5, verbosity=0)
+        suite = runner.build_suite(['test_runner_apps.tagged'])
+        self.assertEqual(suite.processes, len(suite.subsuites))
+
     def test_buffer_mode_test_pass(self):
         runner = DiscoverRunner(buffer=True, verbose=0)
         with captured_stdout() as stdout, captured_stderr() as stderr: