diff --git a/ReactiveObjC/NSObject+RACPropertySubscribing.m b/ReactiveObjC/NSObject+RACPropertySubscribing.m
index 29e3df89e..d7b4b6294 100644
--- a/ReactiveObjC/NSObject+RACPropertySubscribing.m
+++ b/ReactiveObjC/NSObject+RACPropertySubscribing.m
@@ -17,7 +17,6 @@
 #import "RACSubscriber.h"
 #import "RACSignal+Operations.h"
 #import "RACTuple.h"
-#import <libkern/OSAtomic.h>
 
 @implementation NSObject (RACPropertySubscribing)
 
diff --git a/ReactiveObjC/RACCommand.m b/ReactiveObjC/RACCommand.m
index 4342f80ba..db4c6ba98 100644
--- a/ReactiveObjC/RACCommand.m
+++ b/ReactiveObjC/RACCommand.m
@@ -17,14 +17,14 @@
 #import "RACScheduler.h"
 #import "RACSequence.h"
 #import "RACSignal+Operations.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 
 NSErrorDomain const RACCommandErrorDomain = @"RACCommandErrorDomain";
 NSString * const RACUnderlyingCommandErrorKey = @"RACUnderlyingCommandErrorKey";
 
 @interface RACCommand () {
 	// Atomic backing variable for `allowsConcurrentExecution`.
-	volatile uint32_t _allowsConcurrentExecution;
+	atomic_uint _allowsConcurrentExecution;
 }
 
 /// A subject that sends added execution signals.
@@ -53,9 +53,9 @@ - (BOOL)allowsConcurrentExecution {
 
 - (void)setAllowsConcurrentExecution:(BOOL)allowed {
 	if (allowed) {
-		OSAtomicOr32Barrier(1, &_allowsConcurrentExecution);
+		atomic_fetch_or(&_allowsConcurrentExecution, 1);
 	} else {
-		OSAtomicAnd32Barrier(0, &_allowsConcurrentExecution);
+		atomic_fetch_and(&_allowsConcurrentExecution, 0);
 	}
 
 	[self.allowsConcurrentExecutionSubject sendNext:@(_allowsConcurrentExecution)];
diff --git a/ReactiveObjC/RACDisposable.m b/ReactiveObjC/RACDisposable.m
index 3cba07f4f..55e92964e 100644
--- a/ReactiveObjC/RACDisposable.m
+++ b/ReactiveObjC/RACDisposable.m
@@ -8,7 +8,7 @@
 
 #import "RACDisposable.h"
 #import "RACScopedDisposable.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 
 @interface RACDisposable () {
 	// A copied block of type void (^)(void) containing the logic for disposal,
@@ -16,7 +16,7 @@ @interface RACDisposable () {
 	// NULL if the receiver is already disposed.
 	//
 	// This should only be used atomically.
-	void * volatile _disposeBlock;
+	_Atomic(void *) _disposeBlock;
 }
 
 @end
@@ -35,7 +35,7 @@ - (instancetype)init {
 	self = [super init];
 
 	_disposeBlock = (__bridge void *)self;
-	OSMemoryBarrier();
+	atomic_thread_fence(memory_order_seq_cst);
 
 	return self;
 }
@@ -46,7 +46,7 @@ - (instancetype)initWithBlock:(void (^)(void))block {
 	self = [super init];
 
 	_disposeBlock = (void *)CFBridgingRetain([block copy]); 
-	OSMemoryBarrier();
+	atomic_thread_fence(memory_order_seq_cst);
 
 	return self;
 }
@@ -69,7 +69,7 @@ - (void)dispose {
 
 	while (YES) {
 		void *blockPtr = _disposeBlock;
-		if (OSAtomicCompareAndSwapPtrBarrier(blockPtr, NULL, &_disposeBlock)) {
+		if (atomic_compare_exchange_strong(&_disposeBlock, &blockPtr, NULL)) {
 			if (blockPtr != (__bridge void *)self) {
 				disposeBlock = CFBridgingRelease(blockPtr);
 			}
diff --git a/ReactiveObjC/RACDynamicSequence.m b/ReactiveObjC/RACDynamicSequence.m
index 177a22514..863a48f1f 100644
--- a/ReactiveObjC/RACDynamicSequence.m
+++ b/ReactiveObjC/RACDynamicSequence.m
@@ -7,7 +7,7 @@
 //
 
 #import "RACDynamicSequence.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 
 // Determines how RACDynamicSequences will be deallocated before the next one is
 // shifted onto the autorelease pool.
@@ -114,10 +114,10 @@ + (RACSequence *)sequenceWithLazyDependency:(id (^)(void))dependencyBlock headBl
 }
 
 - (void)dealloc {
-	static volatile int32_t directDeallocCount = 0;
+	static atomic_int directDeallocCount = 0;
 
-	if (OSAtomicIncrement32(&directDeallocCount) >= DEALLOC_OVERFLOW_GUARD) {
-		OSAtomicAdd32(-DEALLOC_OVERFLOW_GUARD, &directDeallocCount);
+	if (atomic_fetch_add(&directDeallocCount, 1) + 1 >= DEALLOC_OVERFLOW_GUARD) {
+		atomic_fetch_add(&directDeallocCount, -DEALLOC_OVERFLOW_GUARD);
 
 		// Put this sequence's tail onto the autorelease pool so we stop
 		// recursing.
diff --git a/ReactiveObjC/RACDynamicSignal.m b/ReactiveObjC/RACDynamicSignal.m
index 3bee2f7c2..53d6d2e9e 100644
--- a/ReactiveObjC/RACDynamicSignal.m
+++ b/ReactiveObjC/RACDynamicSignal.m
@@ -12,7 +12,6 @@
 #import "RACPassthroughSubscriber.h"
 #import "RACScheduler+Private.h"
 #import "RACSubscriber.h"
-#import <libkern/OSAtomic.h>
 
 @interface RACDynamicSignal ()
 
diff --git a/ReactiveObjC/RACMulticastConnection.m b/ReactiveObjC/RACMulticastConnection.m
index f59824500..3b6183535 100644
--- a/ReactiveObjC/RACMulticastConnection.m
+++ b/ReactiveObjC/RACMulticastConnection.m
@@ -11,7 +11,7 @@
 #import "RACDisposable.h"
 #import "RACSerialDisposable.h"
 #import "RACSubject.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 
 @interface RACMulticastConnection () {
 	RACSubject *_signal;
@@ -24,7 +24,7 @@ @interface RACMulticastConnection () {
 	//
 	// If the swap is unsuccessful it means that `_sourceSignal` has already been
 	// connected and the caller has no action to take.
-	int32_t volatile _hasConnected;
+	_Atomic(BOOL) _hasConnected;
 }
 
 @property (nonatomic, readonly, strong) RACSignal *sourceSignal;
@@ -51,7 +51,8 @@ - (instancetype)initWithSourceSignal:(RACSignal *)source subject:(RACSubject *)s
 #pragma mark Connecting
 
 - (RACDisposable *)connect {
-	BOOL shouldConnect = OSAtomicCompareAndSwap32Barrier(0, 1, &_hasConnected);
+	BOOL expected = NO;
+	BOOL shouldConnect = atomic_compare_exchange_strong(&_hasConnected, &expected, YES);
 
 	if (shouldConnect) {
 		self.serialDisposable.disposable = [self.sourceSignal subscribe:_signal];
@@ -61,11 +62,11 @@ - (RACDisposable *)connect {
 }
 
 - (RACSignal *)autoconnect {
-	__block volatile int32_t subscriberCount = 0;
+	__block atomic_int subscriberCount = 0;
 
 	return [[RACSignal
 		createSignal:^(id<RACSubscriber> subscriber) {
-			OSAtomicIncrement32Barrier(&subscriberCount);
+			atomic_fetch_add(&subscriberCount, 1);
 
 			RACDisposable *subscriptionDisposable = [self.signal subscribe:subscriber];
 			RACDisposable *connectionDisposable = [self connect];
@@ -73,7 +74,7 @@ - (RACSignal *)autoconnect {
 			return [RACDisposable disposableWithBlock:^{
 				[subscriptionDisposable dispose];
 
-				if (OSAtomicDecrement32Barrier(&subscriberCount) == 0) {
+				if (atomic_fetch_sub(&subscriberCount, 1) - 1 == 0) {
 					[connectionDisposable dispose];
 				}
 			}];
diff --git a/ReactiveObjC/RACSignal+Operations.m b/ReactiveObjC/RACSignal+Operations.m
index 87967adfd..15c10de5e 100644
--- a/ReactiveObjC/RACSignal+Operations.m
+++ b/ReactiveObjC/RACSignal+Operations.m
@@ -26,7 +26,7 @@
 #import "RACSubscriber.h"
 #import "RACTuple.h"
 #import "RACUnit.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 #import <objc/runtime.h>
 
 NSErrorDomain const RACSignalErrorDomain = @"RACSignalErrorDomain";
@@ -646,7 +646,7 @@ - (RACDisposable *)setKeyPath:(NSString *)keyPath onObject:(NSObject *)object ni
 
 	// Purposely not retaining 'object', since we want to tear down the binding
 	// when it deallocates normally.
-	__block void * volatile objectPtr = (__bridge void *)object;
+	__block _Atomic(void *) objectPtr = (__bridge void *)object;
 
 	RACDisposable *subscriptionDisposable = [self subscribeNext:^(id x) {
 		// Possibly spec, possibly compiler bug, but this __bridge cast does not
@@ -698,7 +698,7 @@ - (RACDisposable *)setKeyPath:(NSString *)keyPath onObject:(NSObject *)object ni
 
 		while (YES) {
 			void *ptr = objectPtr;
-			if (OSAtomicCompareAndSwapPtrBarrier(ptr, NULL, &objectPtr)) {
+			if (atomic_compare_exchange_strong(&objectPtr, &ptr, NULL)) {
 				break;
 			}
 		}
@@ -1048,17 +1048,17 @@ - (RACSignal *)subscribeOn:(RACScheduler *)scheduler {
 
 - (RACSignal *)deliverOnMainThread {
 	return [[RACSignal createSignal:^(id<RACSubscriber> subscriber) {
-		__block volatile int32_t queueLength = 0;
+		__block atomic_int queueLength = 0;
 		
 		void (^performOnMainThread)(dispatch_block_t) = ^(dispatch_block_t block) {
-			int32_t queued = OSAtomicIncrement32(&queueLength);
+			int32_t queued = atomic_fetch_add(&queueLength, 1) + 1;
 			if (NSThread.isMainThread && queued == 1) {
 				block();
-				OSAtomicDecrement32(&queueLength);
+				atomic_fetch_sub(&queueLength, 1);
 			} else {
 				dispatch_async(dispatch_get_main_queue(), ^{
 					block();
-					OSAtomicDecrement32(&queueLength);
+					atomic_fetch_sub(&queueLength, 1);
 				});
 			}
 		};
diff --git a/ReactiveObjC/RACSignal.m b/ReactiveObjC/RACSignal.m
index 84607f681..eb79e6039 100644
--- a/ReactiveObjC/RACSignal.m
+++ b/ReactiveObjC/RACSignal.m
@@ -21,7 +21,7 @@
 #import "RACSubject.h"
 #import "RACSubscriber+Private.h"
 #import "RACTuple.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 
 @implementation RACSignal
 
@@ -108,12 +108,12 @@ - (RACSignal *)bind:(RACSignalBindBlock (^)(void))block {
 	return [[RACSignal createSignal:^(id<RACSubscriber> subscriber) {
 		RACSignalBindBlock bindingBlock = block();
 
-		__block volatile int32_t signalCount = 1;   // indicates self
+		__block atomic_int signalCount = 1;   // indicates self
 
 		RACCompoundDisposable *compoundDisposable = [RACCompoundDisposable compoundDisposable];
 
 		void (^completeSignal)(RACDisposable *) = ^(RACDisposable *finishedDisposable) {
-			if (OSAtomicDecrement32Barrier(&signalCount) == 0) {
+			if (atomic_fetch_sub(&signalCount, 1) - 1 == 0) {
 				[subscriber sendCompleted];
 				[compoundDisposable dispose];
 			} else {
@@ -122,7 +122,7 @@ - (RACSignal *)bind:(RACSignalBindBlock (^)(void))block {
 		};
 
 		void (^addSignal)(RACSignal *) = ^(RACSignal *signal) {
-			OSAtomicIncrement32Barrier(&signalCount);
+			atomic_fetch_add(&signalCount, 1);
 
 			RACSerialDisposable *selfDisposable = [[RACSerialDisposable alloc] init];
 			[compoundDisposable addDisposable:selfDisposable];
diff --git a/ReactiveObjC/extobjc/EXTRuntimeExtensions.m b/ReactiveObjC/extobjc/EXTRuntimeExtensions.m
index 99c10e980..3a2dca635 100644
--- a/ReactiveObjC/extobjc/EXTRuntimeExtensions.m
+++ b/ReactiveObjC/extobjc/EXTRuntimeExtensions.m
@@ -11,7 +11,6 @@
 
 #import <ctype.h>
 #import <Foundation/Foundation.h>
-#import <libkern/OSAtomic.h>
 #import <objc/message.h>
 #import <pthread.h>
 #import <stdio.h>
diff --git a/ReactiveObjCTests/RACMulticastConnectionSpec.m b/ReactiveObjCTests/RACMulticastConnectionSpec.m
index 5ce04ba5f..2d0abc0be 100644
--- a/ReactiveObjCTests/RACMulticastConnectionSpec.m
+++ b/ReactiveObjCTests/RACMulticastConnectionSpec.m
@@ -15,7 +15,6 @@
 #import "RACSubscriber.h"
 #import "RACReplaySubject.h"
 #import "RACScheduler.h"
-#import <libkern/OSAtomic.h>
 
 QuickSpecBegin(RACMulticastConnectionSpec)
 
diff --git a/ReactiveObjCTests/RACSchedulerSpec.m b/ReactiveObjCTests/RACSchedulerSpec.m
index 754a8c83e..0199d46d5 100644
--- a/ReactiveObjCTests/RACSchedulerSpec.m
+++ b/ReactiveObjCTests/RACSchedulerSpec.m
@@ -15,7 +15,6 @@
 #import "RACDisposable.h"
 #import <ReactiveObjC/EXTScope.h>
 #import "RACTestExampleScheduler.h"
-#import <libkern/OSAtomic.h>
 
 // This shouldn't be used directly. Use the `expectCurrentSchedulers` block
 // below instead.
diff --git a/ReactiveObjCTests/RACSignalSpec.m b/ReactiveObjCTests/RACSignalSpec.m
index bc65fd547..8c472b68c 100644
--- a/ReactiveObjCTests/RACSignalSpec.m
+++ b/ReactiveObjCTests/RACSignalSpec.m
@@ -33,7 +33,7 @@
 #import "RACTestScheduler.h"
 #import "RACTuple.h"
 #import "RACUnit.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 
 // Set in a beforeAll below.
 static NSError *RACSignalTestError;
@@ -111,7 +111,7 @@ + (void)configure:(Configuration *)configuration {
 	};
 
 	RACSignal *infiniteSignal = [RACSignal createSignal:^(id<RACSubscriber> subscriber) {
-		__block volatile int32_t done = 0;
+		__block atomic_int done = 0;
 
 		[RACScheduler.mainThreadScheduler schedule:^{
 			while (!done) {
@@ -120,7 +120,7 @@ + (void)configure:(Configuration *)configuration {
 		}];
 
 		return [RACDisposable disposableWithBlock:^{
-			OSAtomicIncrement32Barrier(&done);
+			atomic_fetch_add(&done, 1);
 		}];
 	}];
 
diff --git a/ReactiveObjCTests/RACSubjectSpec.m b/ReactiveObjCTests/RACSubjectSpec.m
index bfe56a5b5..5e2a827aa 100644
--- a/ReactiveObjCTests/RACSubjectSpec.m
+++ b/ReactiveObjCTests/RACSubjectSpec.m
@@ -11,7 +11,7 @@
 
 #import "RACSubscriberExamples.h"
 
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 #import <ReactiveObjC/EXTScope.h>
 #import "RACBehaviorSubject.h"
 #import "RACCompoundDisposable.h"
@@ -255,10 +255,10 @@ - (void)didSubscribeWithDisposable:(RACCompoundDisposable *)disposable {
 
 			// Just leak it, ain't no thang.
 			__unsafe_unretained volatile id *values = (__unsafe_unretained id *)calloc(count, sizeof(*values));
-			__block volatile int32_t nextIndex = 0;
+			__block atomic_int nextIndex = 0;
 
 			[subject subscribeNext:^(NSNumber *value) {
-				int32_t indexPlusOne = OSAtomicIncrement32(&nextIndex);
+				int32_t indexPlusOne = atomic_fetch_add(&nextIndex, 1) + 1;
 				values[indexPlusOne - 1] = value;
 			}];
 
@@ -276,7 +276,7 @@ - (void)didSubscribeWithDisposable:(RACCompoundDisposable *)disposable {
 				[subject sendCompleted];
 			});
 
-			OSMemoryBarrier();
+			atomic_thread_fence(memory_order_seq_cst);
 
 			NSArray *liveValues = [NSArray arrayWithObjects:(id *)values count:(NSUInteger)nextIndex];
 			expect(liveValues).to(haveCount(@(count)));
diff --git a/ReactiveObjCTests/RACSubscriberSpec.m b/ReactiveObjCTests/RACSubscriberSpec.m
index 0ff9fba90..834db099b 100644
--- a/ReactiveObjCTests/RACSubscriberSpec.m
+++ b/ReactiveObjCTests/RACSubscriberSpec.m
@@ -13,15 +13,15 @@
 
 #import "RACSubscriber.h"
 #import "RACSubscriber+Private.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 
 QuickSpecBegin(RACSubscriberSpec)
 
 __block RACSubscriber *subscriber;
 __block NSMutableArray *values;
 
-__block volatile BOOL finished;
-__block volatile int32_t nextsAfterFinished;
+__block _Atomic(BOOL) finished;
+__block atomic_int nextsAfterFinished;
 
 __block BOOL success;
 __block NSError *error;
@@ -36,7 +36,7 @@
 	error = nil;
 
 	subscriber = [RACSubscriber subscriberWithNext:^(id value) {
-		if (finished) OSAtomicIncrement32Barrier(&nextsAfterFinished);
+		if (finished) atomic_fetch_add(&nextsAfterFinished, 1);
 
 		[values addObject:value];
 	} error:^(NSError *e) {
@@ -111,7 +111,7 @@
 			[subscriber sendCompleted];
 
 			finished = YES;
-			OSMemoryBarrier();
+			atomic_thread_fence(memory_order_seq_cst);
 		});
 	});
 
@@ -122,7 +122,7 @@
 			[subscriber sendError:nil];
 
 			finished = YES;
-			OSMemoryBarrier();
+			atomic_thread_fence(memory_order_seq_cst);
 		});
 	});
 });
diff --git a/ReactiveObjCTests/RACTargetQueueSchedulerSpec.m b/ReactiveObjCTests/RACTargetQueueSchedulerSpec.m
index c112bcd4a..6b12c9421 100644
--- a/ReactiveObjCTests/RACTargetQueueSchedulerSpec.m
+++ b/ReactiveObjCTests/RACTargetQueueSchedulerSpec.m
@@ -10,7 +10,7 @@
 @import Nimble;
 
 #import "RACTargetQueueScheduler.h"
-#import <libkern/OSAtomic.h>
+#import <stdatomic.h>
 
 QuickSpecBegin(RACTargetQueueSchedulerSpec)
 
@@ -28,20 +28,20 @@
 qck_it(@"should schedule blocks FIFO even when given a concurrent queue", ^{
 	dispatch_queue_t queue = dispatch_queue_create("test-queue", DISPATCH_QUEUE_CONCURRENT);
 	RACScheduler *scheduler = [[RACTargetQueueScheduler alloc] initWithName:@"test-scheduler" targetQueue:queue];
-	__block volatile int32_t startedCount = 0;
-	__block volatile uint32_t waitInFirst = 1;
+	__block atomic_int startedCount = 0;
+	__block atomic_uint waitInFirst = 1;
 	[scheduler schedule:^{
-		OSAtomicIncrement32Barrier(&startedCount);
+		atomic_fetch_add(&startedCount, 1);
 		while (waitInFirst == 1) ;
 	}];
 
 	[scheduler schedule:^{
-		OSAtomicIncrement32Barrier(&startedCount);
+		atomic_fetch_add(&startedCount, 1);
 	}];
 
 	expect(@(startedCount)).toEventually(equal(@1));
 
-	OSAtomicAnd32Barrier(0, &waitInFirst);
+	atomic_fetch_and(&waitInFirst, 0);
 
 	expect(@(startedCount)).toEventually(equal(@2));
 });