diff --git a/kernel/fatal.c b/kernel/fatal.c
index e73608a3bb1..cd2876b5253 100644
--- a/kernel/fatal.c
+++ b/kernel/fatal.c
@@ -48,9 +48,9 @@ __weak void k_sys_fatal_error_handler(unsigned int reason,
 
 static const char *thread_name_get(struct k_thread *thread)
 {
-	const char *thread_name = thread ? k_thread_name_get(thread) : NULL;
+	const char *thread_name = (thread != NULL) ? k_thread_name_get(thread) : NULL;
 
-	if (thread_name == NULL || thread_name[0] == '\0') {
+	if ((thread_name == NULL) || (thread_name[0] == '\0')) {
 		thread_name = "unknown";
 	}
 
diff --git a/kernel/futex.c b/kernel/futex.c
index 2f87e3199a0..d06641328b3 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -40,7 +40,7 @@ int z_impl_k_futex_wake(struct k_futex *futex, bool wake_all)
 
 	do {
 		thread = z_unpend_first_thread(&futex_data->wait_q);
-		if (thread) {
+		if (thread != NULL) {
 			woken++;
 			arch_thread_return_value_set(thread, 0);
 			z_ready_thread(thread);
diff --git a/kernel/mempool.c b/kernel/mempool.c
index 3def6c727cc..295bb2259a2 100644
--- a/kernel/mempool.c
+++ b/kernel/mempool.c
@@ -103,7 +103,7 @@ void *z_thread_aligned_alloc(size_t align, size_t size)
 		heap = _current->resource_pool;
 	}
 
-	if (heap) {
+	if (heap != NULL) {
 		ret = z_heap_aligned_alloc(heap, align, size);
 	} else {
 		ret = NULL;
diff --git a/kernel/poll.c b/kernel/poll.c
index 56886db0aab..376f51b2c66 100644
--- a/kernel/poll.c
+++ b/kernel/poll.c
@@ -387,7 +387,7 @@ static int signal_poll_event(struct k_poll_event *event, uint32_t state)
 	struct z_poller *poller = event->poller;
 	int retcode = 0;
 
-	if (poller) {
+	if (poller != NULL) {
 		if (poller->mode == MODE_POLL) {
 			retcode = signal_poller(event, state);
 		} else if (poller->mode == MODE_TRIGGERED) {
diff --git a/kernel/sched.c b/kernel/sched.c
index 1f1c7ee6659..372ddc6ac34 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -268,7 +268,7 @@ static ALWAYS_INLINE struct k_thread *next_up(void)
 	 * responsible for putting it back in z_swap and ISR return!),
 	 * which makes this choice simple.
 	 */
-	return thread ? thread : _current_cpu->idle_thread;
+	return (thread != NULL) ? thread : _current_cpu->idle_thread;
 #else
 	/* Under SMP, the "cache" mechanism for selecting the next
 	 * thread doesn't work, so we have more work to do to test
@@ -781,7 +781,7 @@ void z_thread_priority_set(struct k_thread *thread, int prio)
 	}
 }
 
-static inline int resched(uint32_t key)
+static inline bool resched(uint32_t key)
 {
 #ifdef CONFIG_SMP
 	_current_cpu->swap_ok = 0;
@@ -1481,7 +1481,7 @@ void z_thread_abort(struct k_thread *thread)
 {
 	k_spinlock_key_t key = k_spin_lock(&sched_spinlock);
 
-	if (thread->base.thread_state & _THREAD_DEAD) {
+	if ((thread->base.thread_state & _THREAD_DEAD) != 0U) {
 		k_spin_unlock(&sched_spinlock, key);
 		return;
 	}
@@ -1537,12 +1537,12 @@ int z_impl_k_thread_join(struct k_thread *thread, k_timeout_t timeout)
 	k_spinlock_key_t key = k_spin_lock(&sched_spinlock);
 	int ret = 0;
 
-	if (thread->base.thread_state & _THREAD_DEAD) {
+	if ((thread->base.thread_state & _THREAD_DEAD) != 0U) {
 		ret = 0;
 	} else if (K_TIMEOUT_EQ(timeout, K_NO_WAIT)) {
 		ret = -EBUSY;
-	} else if (thread == _current ||
-		   thread->base.pended_on == &_current->join_queue) {
+	} else if ((thread == _current) ||
+		   (thread->base.pended_on == &_current->join_queue)) {
 		ret = -EDEADLK;
 	} else {
 		__ASSERT(!arch_is_in_isr(), "cannot join in ISR");
diff --git a/kernel/thread.c b/kernel/thread.c
index 04abfa8b30b..f9e2f5b5cb0 100644
--- a/kernel/thread.c
+++ b/kernel/thread.c
@@ -844,7 +844,7 @@ bool z_spin_lock_valid(struct k_spinlock *l)
 {
 	uintptr_t thread_cpu = l->thread_cpu;
 
-	if (thread_cpu) {
+	if (thread_cpu != 0U) {
 		if ((thread_cpu & 3U) == _current_cpu->id) {
 			return false;
 		}