diff --git a/kernel/include/ksched.h b/kernel/include/ksched.h
index c7c927ef377..f38b21abbe7 100644
--- a/kernel/include/ksched.h
+++ b/kernel/include/ksched.h
@@ -87,7 +87,7 @@ static inline bool z_is_idle_thread(void *entry_point)
 
 static inline bool z_is_thread_pending(struct k_thread *thread)
 {
-	return !!(thread->base.thread_state & _THREAD_PENDING);
+	return (thread->base.thread_state & _THREAD_PENDING) != 0;
 }
 
 static inline bool z_is_thread_prevented_from_running(struct k_thread *thread)
@@ -117,7 +117,7 @@ static inline bool z_has_thread_started(struct k_thread *thread)
 
 static inline bool z_is_thread_state_set(struct k_thread *thread, u32_t state)
 {
-	return !!(thread->base.thread_state & state);
+	return (thread->base.thread_state & state) != 0;
 }
 
 static inline bool z_is_thread_queued(struct k_thread *thread)
diff --git a/kernel/msg_q.c b/kernel/msg_q.c
index 460c05c9db4..b796e74db9b 100644
--- a/kernel/msg_q.c
+++ b/kernel/msg_q.c
@@ -101,7 +101,7 @@ Z_SYSCALL_HANDLER(k_msgq_alloc_init, q, msg_size, max_msgs)
 
 void k_msgq_cleanup(struct k_msgq *q)
 {
-	__ASSERT_NO_MSG(!z_waitq_head(&q->wait_q));
+	__ASSERT_NO_MSG(z_waitq_head(&q->wait_q) == NULL);
 
 	if ((q->flags & K_MSGQ_FLAG_ALLOC) != 0) {
 		k_free(q->buffer_start);
diff --git a/kernel/sched.c b/kernel/sched.c
index 01f659a305f..1c28eb688e7 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -73,9 +73,9 @@ static inline int is_metairq(struct k_thread *thread)
 }
 
 #if CONFIG_ASSERT
-static inline int is_thread_dummy(struct k_thread *thread)
+static inline bool is_thread_dummy(struct k_thread *thread)
 {
-	return !!(thread->base.thread_state & _THREAD_DUMMY);
+	return (thread->base.thread_state & _THREAD_DUMMY) != 0;
 }
 #endif
 
diff --git a/kernel/timeout.c b/kernel/timeout.c
index d4f85b0cddf..a24f0b4b6e4 100644
--- a/kernel/timeout.c
+++ b/kernel/timeout.c
@@ -12,7 +12,7 @@
 
 #define LOCKED(lck) for (k_spinlock_key_t __i = {},			\
 					  __key = k_spin_lock(lck);	\
-			!__i.key;					\
+			__i.key == 0;					\
 			k_spin_unlock(lck, __key), __i.key = 1)
 
 static u64_t curr_tick;
diff --git a/kernel/userspace.c b/kernel/userspace.c
index 77dbe150301..a39f41df57b 100644
--- a/kernel/userspace.c
+++ b/kernel/userspace.c
@@ -558,19 +558,19 @@ int z_object_validate(struct _k_object *ko, enum k_objects otype,
 	/* Manipulation of any kernel objects by a user thread requires that
 	 * thread be granted access first, even for uninitialized objects
 	 */
-	if (unlikely(!thread_perms_test(ko))) {
+	if (unlikely(thread_perms_test(ko) == 0)) {
 		return -EPERM;
 	}
 
 	/* Initialization state checks. _OBJ_INIT_ANY, we don't care */
 	if (likely(init == _OBJ_INIT_TRUE)) {
 		/* Object MUST be intialized */
-		if (unlikely(!(ko->flags & K_OBJ_FLAG_INITIALIZED))) {
+		if (unlikely((ko->flags & K_OBJ_FLAG_INITIALIZED) == 0)) {
 			return -EINVAL;
 		}
 	} else if (init < _OBJ_INIT_TRUE) { /* _OBJ_INIT_FALSE case */
 		/* Object MUST NOT be initialized */
-		if (unlikely(ko->flags & K_OBJ_FLAG_INITIALIZED)) {
+		if (unlikely((ko->flags & K_OBJ_FLAG_INITIALIZED) != 0)) {
 			return -EADDRINUSE;
 		}
 	} else {
diff --git a/kernel/work_q.c b/kernel/work_q.c
index 9f21b8d290f..2558d6e831e 100644
--- a/kernel/work_q.c
+++ b/kernel/work_q.c
@@ -79,7 +79,7 @@ int k_delayed_work_submit_to_queue(struct k_work_q *work_q,
 	int err = 0;
 
 	/* Work cannot be active in multiple queues */
-	if (work->work_q && work->work_q != work_q) {
+	if (work->work_q != NULL && work->work_q != work_q) {
 		err = -EADDRINUSE;
 		goto done;
 	}
@@ -98,7 +98,7 @@ int k_delayed_work_submit_to_queue(struct k_work_q *work_q,
 	/* Submit work directly if no delay.  Note that this is a
 	 * blocking operation, so release the lock first.
 	 */
-	if (!delay) {
+	if (delay == 0) {
 		k_spin_unlock(&lock, key);
 		k_work_submit_to_queue(work_q, &work->work);
 		return 0;