diff --git a/tests/sys_sema_inv/Makefile b/tests/sys_sema_inv/Makefile
new file mode 100644
index 0000000000..f846bd01df
--- /dev/null
+++ b/tests/sys_sema_inv/Makefile
@@ -0,0 +1,6 @@
+include ../Makefile.tests_common
+
+USEMODULE += sema_inv
+USEMODULE += xtimer
+
+include $(RIOTBASE)/Makefile.include
diff --git a/tests/sys_sema_inv/Makefile.ci b/tests/sys_sema_inv/Makefile.ci
new file mode 100644
index 0000000000..ff454e3604
--- /dev/null
+++ b/tests/sys_sema_inv/Makefile.ci
@@ -0,0 +1,7 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    arduino-duemilanove \
+    arduino-nano \
+    arduino-uno \
+    atmega328p \
+    nucleo-l011k4 \
+    #
diff --git a/tests/sys_sema_inv/main.c b/tests/sys_sema_inv/main.c
new file mode 100644
index 0000000000..62c8dd6014
--- /dev/null
+++ b/tests/sys_sema_inv/main.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2021 ML!PA Consulting GmbH
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup tests
+ * @{
+ *
+ * @file
+ * @brief   Inverse Semaphore Test Application
+ *
+ * @author  Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ * @}
+ */
+
+#include <assert.h>
+#include <stdio.h>
+
+#include "sema_inv.h"
+#include "xtimer.h"
+
+char t1_stack[THREAD_STACKSIZE_SMALL];
+char t2_stack[THREAD_STACKSIZE_SMALL];
+char t3_stack[THREAD_STACKSIZE_SMALL];
+
+struct thread_ctx {
+    sema_inv_t *sync;
+    unsigned id;
+};
+
+static void *thread_count(void *arg)
+{
+    struct thread_ctx *ctx = arg;
+
+    printf("THREAD %u start\n", ctx->id);
+
+    xtimer_msleep(5);
+
+    if (sema_inv_post(ctx->sync)) {
+        printf("THREAD %u woke main thread\n", ctx->id);
+    }
+
+    return arg;
+}
+
+static void *thread_bit(void *arg)
+{
+    struct thread_ctx *ctx = arg;
+
+    printf("THREAD %u start\n", ctx->id);
+
+    xtimer_msleep(5);
+
+    if (sema_inv_post_mask(ctx->sync, 1 << ctx->id)) {
+        printf("THREAD %u woke main thread\n", ctx->id);
+    }
+
+    return arg;
+}
+
+static void test_counter_mode(void)
+{
+    sema_inv_t sync;
+
+    struct thread_ctx ctx[3] = {
+        { .sync = &sync, .id = 1 },
+        { .sync = &sync, .id = 2 },
+        { .sync = &sync, .id = 3 },
+    };
+
+    puts("counter mode");
+    sema_inv_init(&sync, 3);
+
+    thread_create(t1_stack, sizeof(t1_stack), THREAD_PRIORITY_MAIN - 1,
+                  THREAD_CREATE_STACKTEST, thread_count, &ctx[0], "nr1");
+    thread_create(t2_stack, sizeof(t2_stack), THREAD_PRIORITY_MAIN + 1,
+                  THREAD_CREATE_STACKTEST, thread_count, &ctx[1], "nr2");
+    thread_create(t3_stack, sizeof(t3_stack), THREAD_PRIORITY_MAIN + 1,
+                  THREAD_CREATE_STACKTEST, thread_count, &ctx[2], "nr3");
+
+    sema_inv_wait(&sync);
+    puts("thread synced");
+
+    /* wait for all threads to terminate, we are going to re-use the stack */
+    xtimer_msleep(10);
+}
+
+static void test_mask_mode(void)
+{
+    sema_inv_t sync;
+
+    struct thread_ctx ctx[3] = {
+        { .sync = &sync, .id = 1 },
+        { .sync = &sync, .id = 2 },
+        { .sync = &sync, .id = 3 },
+    };
+
+    puts("mask mode");
+    sema_inv_init(&sync, 0xE);
+
+    thread_create(t1_stack, sizeof(t1_stack), THREAD_PRIORITY_MAIN - 1,
+                  THREAD_CREATE_STACKTEST, thread_bit, &ctx[0], "nr1");
+    thread_create(t2_stack, sizeof(t2_stack), THREAD_PRIORITY_MAIN + 1,
+                  THREAD_CREATE_STACKTEST, thread_bit, &ctx[1], "nr2");
+    thread_create(t3_stack, sizeof(t3_stack), THREAD_PRIORITY_MAIN + 1,
+                  THREAD_CREATE_STACKTEST, thread_bit, &ctx[2], "nr3");
+
+    sema_inv_wait(&sync);
+    puts("thread synced");
+
+    /* wait for all threads to terminate, we are going to re-use the stack */
+    xtimer_msleep(10);
+}
+
+int main(void)
+{
+    test_counter_mode();
+    test_mask_mode();
+
+    puts("SUCCESS");
+
+    return 0;
+}
diff --git a/tests/sys_sema_inv/tests/01-run.py b/tests/sys_sema_inv/tests/01-run.py
new file mode 100755
index 0000000000..d14d3c5980
--- /dev/null
+++ b/tests/sys_sema_inv/tests/01-run.py
@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+
+import sys
+from testrunner import run
+
+
+def testfunc(child):
+    child.expect_exact('counter mode')
+    child.expect_exact('THREAD 1 start')
+    child.expect_exact('THREAD 2 start')
+    child.expect_exact('THREAD 3 start')
+    child.expect_exact('thread synced')
+    child.expect_exact('THREAD 3 woke main thread')
+
+    child.expect_exact('mask mode')
+    child.expect_exact('THREAD 1 start')
+    child.expect_exact('THREAD 2 start')
+    child.expect_exact('THREAD 3 start')
+    child.expect_exact('thread synced')
+    child.expect_exact('THREAD 3 woke main thread')
+
+    child.expect_exact('SUCCESS')
+
+
+if __name__ == "__main__":
+    sys.exit(run(testfunc))