diff --git a/tests/unittests/tests-bit/Makefile b/tests/unittests/tests-bit/Makefile
new file mode 100644
index 0000000000..48422e909a
--- /dev/null
+++ b/tests/unittests/tests-bit/Makefile
@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base
diff --git a/tests/unittests/tests-bit/tests-bit.c b/tests/unittests/tests-bit/tests-bit.c
new file mode 100644
index 0000000000..43918bf03f
--- /dev/null
+++ b/tests/unittests/tests-bit/tests-bit.c
@@ -0,0 +1,108 @@
+/*
+ * SPDX-FileCopyrightText: 2025 ML!PA Consulting GmbH
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+/**
+ * @{
+ *
+ * @file
+ * @author  Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ *
+ * @}
+ */
+
+#include <errno.h>
+#include "embUnit.h"
+
+#include "bit.h"
+
+static void test_bit8(void)
+{
+    uint8_t tmp, word = UINT8_MAX;
+
+    for (unsigned i = 0; i < sizeof(word) * 8; ++i) {
+        TEST_ASSERT_EQUAL_INT(1, bit_check8(&word, i));
+    }
+
+    tmp = word;
+    for (unsigned i = 0; i < sizeof(word) * 8; i += 2) {
+        bit_clear8(&word, i);
+        tmp &= ~(1UL << i);
+        TEST_ASSERT_EQUAL_INT(tmp, word);
+    }
+
+    word <<= 1;
+    tmp = word;
+    for (unsigned i = 1; i < sizeof(word) * 8; i += 2) {
+        bit_set8(&word, i);
+        tmp |= 1UL << i;
+        TEST_ASSERT_EQUAL_INT(tmp, word);
+    }
+}
+
+static void test_bit16(void)
+{
+    uint16_t tmp, word = UINT16_MAX;
+
+    for (unsigned i = 0; i < sizeof(word) * 8; ++i) {
+        TEST_ASSERT_EQUAL_INT(1, bit_check16(&word, i));
+    }
+
+    tmp = word;
+    for (unsigned i = 0; i < sizeof(word) * 8; i += 2) {
+        bit_clear16(&word, i);
+        tmp &= ~(1UL << i);
+        TEST_ASSERT_EQUAL_INT(tmp, word);
+    }
+
+    word <<= 1;
+    tmp = word;
+    for (unsigned i = 1; i < sizeof(word) * 8; i += 2) {
+        bit_set16(&word, i);
+        tmp |= 1UL << i;
+        TEST_ASSERT_EQUAL_INT(tmp, word);
+    }
+}
+
+static void test_bit32(void)
+{
+    uint32_t tmp, word = UINT32_MAX;
+
+    for (unsigned i = 0; i < sizeof(word) * 8; ++i) {
+        TEST_ASSERT_EQUAL_INT(1, bit_check32(&word, i));
+    }
+
+    tmp = word;
+    for (unsigned i = 0; i < sizeof(word) * 8; i += 2) {
+        bit_clear32(&word, i);
+        tmp &= ~(1UL << i);
+        TEST_ASSERT_EQUAL_INT(tmp, word);
+    }
+
+    word <<= 1;
+    tmp = word;
+    for (unsigned i = 1; i < sizeof(word) * 8; i += 2) {
+        bit_set32(&word, i);
+        tmp |= 1UL << i;
+        TEST_ASSERT_EQUAL_INT(tmp, word);
+    }
+}
+
+Test *tests_bit_tests(void)
+{
+    EMB_UNIT_TESTFIXTURES(fixtures) {
+        new_TestFixture(test_bit8),
+        new_TestFixture(test_bit16),
+        new_TestFixture(test_bit32),
+    };
+
+    EMB_UNIT_TESTCALLER(bit_tests, NULL, NULL, fixtures);
+
+    return (Test *)&bit_tests;
+}
+
+void tests_bit(void)
+{
+    TESTS_RUN(tests_bit_tests());
+}
diff --git a/tests/unittests/tests-bit/tests-bit.h b/tests/unittests/tests-bit/tests-bit.h
new file mode 100644
index 0000000000..68a2c1cc6e
--- /dev/null
+++ b/tests/unittests/tests-bit/tests-bit.h
@@ -0,0 +1,43 @@
+/*
+ * SPDX-FileCopyrightText: 2025 ML!PA Consulting GmbH
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+#pragma once
+
+/**
+ * @addtogroup  unittests
+ * @{
+ *
+ * @file
+ * @brief   Unittests for the `bit` header
+ *
+ *          This verifies that the functions to test/set/clear individual bits
+ *          (which may use hardware specific instructions to do so) work.
+ *
+ * @author  Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ */
+
+#include "embUnit/embUnit.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+*  @brief   The entry point of this test suite.
+*/
+void tests_bit(void);
+
+/**
+ * @brief   Generates tests for bit header
+ *
+ * @return  embUnit tests if successful, NULL if not.
+ */
+Test *tests_bit_tests(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+/** @} */