diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index a99b8ec..1466d25 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -1057,8 +1057,6 @@
         lock = threading.Lock()
         self.assertRaises(RuntimeError, lock.release)
 
-    @unittest.skipUnless(sys.platform == 'darwin' and test.support.python_is_optimized(),
-                         'test macosx problem')
     def test_recursion_limit(self):
         # Issue 9670
         # test that excessive recursion within a non-main thread causes
diff --git a/Misc/NEWS.d/next/macOS/2019-07-13-15-58-18.bpo-18049.MklhQQ.rst b/Misc/NEWS.d/next/macOS/2019-07-13-15-58-18.bpo-18049.MklhQQ.rst
new file mode 100644
index 0000000..5af07cd
--- /dev/null
+++ b/Misc/NEWS.d/next/macOS/2019-07-13-15-58-18.bpo-18049.MklhQQ.rst
@@ -0,0 +1,3 @@
+Increase the default stack size of threads from 5MB to 16MB on macOS, to
+match the stack size of the main thread. This avoids crashes on deep recursion
+in threads.
diff --git a/Python/thread_pthread.h b/Python/thread_pthread.h
index a36d16c..994e35b 100644
--- a/Python/thread_pthread.h
+++ b/Python/thread_pthread.h
@@ -40,7 +40,8 @@
  */
 #if defined(__APPLE__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
 #undef  THREAD_STACK_SIZE
-#define THREAD_STACK_SIZE       0x500000
+/* Note: This matches the value of -Wl,-stack_size in configure.ac */
+#define THREAD_STACK_SIZE       0x1000000
 #endif
 #if defined(__FreeBSD__) && defined(THREAD_STACK_SIZE) && THREAD_STACK_SIZE == 0
 #undef  THREAD_STACK_SIZE
diff --git a/configure b/configure
index 4cea98e..bffb849 100755
--- a/configure
+++ b/configure
@@ -9542,6 +9542,8 @@
 		# Issue #18075: the default maximum stack size (8MBytes) is too
 		# small for the default recursion limit. Increase the stack size
 		# to ensure that tests don't crash
+		# Note: This matches the value of THREAD_STACK_SIZE in
+		# thread_pthread.h
 		LINKFORSHARED="-Wl,-stack_size,1000000 $LINKFORSHARED"
 
 		if test "$enable_framework"
diff --git a/configure.ac b/configure.ac
index b9759e1..8566d43 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2694,6 +2694,8 @@
 		# Issue #18075: the default maximum stack size (8MBytes) is too
 		# small for the default recursion limit. Increase the stack size
 		# to ensure that tests don't crash
+		# Note: This matches the value of THREAD_STACK_SIZE in
+		# thread_pthread.h
 		LINKFORSHARED="-Wl,-stack_size,1000000 $LINKFORSHARED"
 
 		if test "$enable_framework"