diff --git a/tests/isc/Makefile.am b/tests/isc/Makefile.am
index 0db34d7ace..1a3650e3b9 100644
--- a/tests/isc/Makefile.am
+++ b/tests/isc/Makefile.am
@@ -32,6 +32,7 @@ check_PROGRAMS =	\
 	loop_test	\
 	md_test		\
 	mem_test	\
+	mutex_test	\
 	netaddr_test	\
 	parse_test	\
 	quota_test	\
diff --git a/tests/isc/mutex_test.c b/tests/isc/mutex_test.c
new file mode 100644
index 0000000000..26a54c85fd
--- /dev/null
+++ b/tests/isc/mutex_test.c
@@ -0,0 +1,215 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <fcntl.h>
+#include <sched.h> /* IWYU pragma: keep */
+#include <setjmp.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define UNIT_TESTING
+#include <cmocka.h>
+
+#include <isc/atomic.h>
+#include <isc/file.h>
+#include <isc/mem.h>
+#include <isc/mutex.h>
+#include <isc/os.h>
+#include <isc/pause.h>
+#include <isc/result.h>
+#include <isc/stdio.h>
+#include <isc/thread.h>
+#include <isc/time.h>
+#include <isc/util.h>
+
+#include <tests/isc.h>
+
+static unsigned int loops = 100;
+static unsigned int delay_loop = 1;
+
+static int
+setup_env(void **unused __attribute__((__unused__))) {
+	char *env = getenv("ISC_BENCHMARK_LOOPS");
+	if (env != NULL) {
+		loops = atoi(env);
+	}
+	assert_int_not_equal(loops, 0);
+
+	env = getenv("ISC_BENCHMARK_DELAY");
+	if (env != NULL) {
+		delay_loop = atoi(env);
+	}
+	assert_int_not_equal(delay_loop, 0);
+
+	return (0);
+}
+
+ISC_RUN_TEST_IMPL(isc_mutex) {
+	isc_mutex_t lock;
+
+	isc_mutex_init(&lock);
+
+	for (size_t i = 0; i < loops; i++) {
+		isc_mutex_lock(&lock);
+		isc_pause_n(delay_loop);
+		isc_mutex_unlock(&lock);
+	}
+
+	isc_mutex_destroy(&lock);
+}
+
+#define ITERS 20
+
+#define DC	200
+#define CNT_MIN 800
+#define CNT_MAX 1600
+
+static size_t shared_counter = 0;
+static size_t expected_counter = SIZE_MAX;
+static isc_mutex_t lock;
+static pthread_mutex_t mutex;
+
+static isc_threadresult_t
+pthread_mutex_thread(isc_threadarg_t arg) {
+	size_t cont = *(size_t *)arg;
+
+	for (size_t i = 0; i < loops; i++) {
+		pthread_mutex_lock(&mutex);
+		size_t v = shared_counter;
+		isc_pause_n(delay_loop);
+		shared_counter = v + 1;
+		pthread_mutex_unlock(&mutex);
+		isc_pause_n(cont);
+	}
+
+	return ((isc_threadresult_t)0);
+}
+
+static isc_threadresult_t
+isc_mutex_thread(isc_threadarg_t arg) {
+	size_t cont = *(size_t *)arg;
+
+	for (size_t i = 0; i < loops; i++) {
+		isc_mutex_lock(&lock);
+		size_t v = shared_counter;
+		isc_pause_n(delay_loop);
+		shared_counter = v + 1;
+		isc_mutex_unlock(&lock);
+		isc_pause_n(cont);
+	}
+
+	return ((isc_threadresult_t)0);
+}
+
+ISC_RUN_TEST_IMPL(isc_mutex_benchmark) {
+	isc_thread_t *threads = isc_mem_get(mctx, sizeof(*threads) * workers);
+	isc_time_t ts1, ts2;
+	double t;
+	int dc;
+	size_t cont;
+	int r;
+
+	memset(threads, 0, sizeof(*threads) * workers);
+
+	expected_counter = ITERS * workers * loops *
+			   ((CNT_MAX - CNT_MIN) / DC + 1);
+
+	/* PTHREAD MUTEX */
+
+	r = pthread_mutex_init(&mutex, NULL);
+	assert_int_not_equal(r, -1);
+
+	ts1 = isc_time_now_hires();
+
+	shared_counter = 0;
+	dc = DC;
+	for (size_t l = 0; l < ITERS; l++) {
+		for (cont = (dc > 0) ? CNT_MIN : CNT_MAX;
+		     cont <= CNT_MAX && cont >= CNT_MIN; cont += dc)
+		{
+			for (size_t i = 0; i < workers; i++) {
+				isc_thread_create(pthread_mutex_thread, &cont,
+						  &threads[i]);
+			}
+			for (size_t i = 0; i < workers; i++) {
+				isc_thread_join(threads[i], NULL);
+			}
+		}
+		dc = -dc;
+	}
+	assert_int_equal(shared_counter, expected_counter);
+
+	ts2 = isc_time_now_hires();
+
+	t = isc_time_microdiff(&ts2, &ts1);
+
+	printf("[ TIME     ] isc_mutex_benchmark: %zu pthread_mutex "
+	       "loops in "
+	       "%u threads, %2.3f seconds, %2.3f calls/second\n",
+	       shared_counter, workers, t / 1000000.0,
+	       shared_counter / (t / 1000000.0));
+
+	r = pthread_mutex_destroy(&mutex);
+	assert_int_not_equal(r, -1);
+
+	/* ISC MUTEX */
+
+	isc_mutex_init(&lock);
+
+	ts1 = isc_time_now_hires();
+
+	dc = DC;
+	shared_counter = 0;
+	for (size_t l = 0; l < ITERS; l++) {
+		for (cont = (dc > 0) ? CNT_MIN : CNT_MAX;
+		     cont <= CNT_MAX && cont >= CNT_MIN; cont += dc)
+		{
+			for (size_t i = 0; i < workers; i++) {
+				isc_thread_create(isc_mutex_thread, &cont,
+						  &threads[i]);
+			}
+			for (size_t i = 0; i < workers; i++) {
+				isc_thread_join(threads[i], NULL);
+			}
+		}
+		dc = -dc;
+	}
+	assert_int_equal(shared_counter, expected_counter);
+
+	ts2 = isc_time_now_hires();
+
+	t = isc_time_microdiff(&ts2, &ts1);
+
+	printf("[ TIME     ] isc_mutex_benchmark: %zu isc_mutex loops "
+	       "in %u "
+	       "threads, %2.3f seconds, %2.3f calls/second\n",
+	       shared_counter, workers, t / 1000000.0,
+	       shared_counter / (t / 1000000.0));
+
+	isc_mutex_destroy(&lock);
+
+	isc_mem_put(mctx, threads, sizeof(*threads) * workers);
+}
+
+ISC_TEST_LIST_START
+
+ISC_TEST_ENTRY(isc_mutex)
+#if !defined(__SANITIZE_THREAD__)
+ISC_TEST_ENTRY(isc_mutex_benchmark)
+#endif /* __SANITIZE_THREAD__ */
+
+ISC_TEST_LIST_END
+
+ISC_TEST_MAIN_CUSTOM(setup_env, NULL)