diff --git a/libc-test/build.rs b/libc-test/build.rs
index 0e56050b008de..5376c46860d6d 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -231,6 +231,7 @@ fn test_apple(target: &str) {
         "netinet/ip.h",
         "netinet/tcp.h",
         "netinet/udp.h",
+        "os/lock.h",
         "poll.h",
         "pthread.h",
         "pthread_spis.h",
@@ -2442,6 +2443,8 @@ fn test_emscripten(target: &str) {
             // Just pass all these through, no need for a "struct" prefix
             "FILE" | "fd_set" | "Dl_info" | "DIR" => ty.to_string(),
 
+            "os_unfair_lock" => "struct os_unfair_lock_s".to_string(),
+
             t if is_union => format!("union {}", t),
 
             t if t.ends_with("_t") => t.to_string(),
diff --git a/libc-test/semver/apple.txt b/libc-test/semver/apple.txt
index cb646e686bfe8..83cd77d9a23db 100644
--- a/libc-test/semver/apple.txt
+++ b/libc-test/semver/apple.txt
@@ -1003,6 +1003,7 @@ OFDEL
 OFILL
 OLD_TIME
 ONOEOT
+OS_UNFAIR_LOCK_INIT
 OXTABS
 O_ASYNC
 O_DSYNC
@@ -1993,6 +1994,14 @@ open_memstream
 open_wmemstream
 openat
 openpty
+os_unfair_lock
+os_unfair_lock_s
+os_unfair_lock_t
+os_unfair_lock_lock
+os_unfair_lock_trylock
+os_unfair_lock_unlock
+os_unfair_lock_assert_owner
+os_unfair_lock_assert_not_owner
 pause
 policy_t
 popen
diff --git a/src/unix/bsd/apple/mod.rs b/src/unix/bsd/apple/mod.rs
index cee87ffbfc490..a9438ef57a3c2 100644
--- a/src/unix/bsd/apple/mod.rs
+++ b/src/unix/bsd/apple/mod.rs
@@ -121,6 +121,9 @@ pub type pthread_introspection_hook_t =
     extern "C" fn(event: ::c_uint, thread: ::pthread_t, addr: *mut ::c_void, size: ::size_t);
 pub type pthread_jit_write_callback_t = ::Option<extern "C" fn(ctx: *mut ::c_void) -> ::c_int>;
 
+pub type os_unfair_lock = os_unfair_lock_s;
+pub type os_unfair_lock_t = *mut os_unfair_lock;
+
 pub type vm_statistics_t = *mut vm_statistics;
 pub type vm_statistics_data_t = vm_statistics;
 pub type vm_statistics64_t = *mut vm_statistics64;
@@ -1295,6 +1298,10 @@ s_no_extra_traits! {
         pub l2p_contigbytes: ::off_t,
         pub l2p_devoffset: ::off_t,
     }
+
+    pub struct os_unfair_lock_s {
+        _os_unfair_lock_opaque: u32,
+    }
 }
 
 impl siginfo_t {
@@ -2576,6 +2583,27 @@ cfg_if! {
                 l2p_devoffset.hash(state);
             }
         }
+        impl PartialEq for os_unfair_lock {
+            fn eq(&self, other: &os_unfair_lock) -> bool {
+                self._os_unfair_lock_opaque == other._os_unfair_lock_opaque
+            }
+        }
+
+        impl Eq for os_unfair_lock {}
+
+        impl ::fmt::Debug for os_unfair_lock {
+            fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
+                f.debug_struct("os_unfair_lock")
+                    .field("_os_unfair_lock_opaque", &self._os_unfair_lock_opaque)
+                    .finish()
+            }
+        }
+
+        impl ::hash::Hash for os_unfair_lock {
+            fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
+                self._os_unfair_lock_opaque.hash(state);
+            }
+        }
     }
 }
 
@@ -3863,6 +3891,10 @@ pub const PTHREAD_RWLOCK_INITIALIZER: pthread_rwlock_t = pthread_rwlock_t {
     __opaque: [0; __PTHREAD_RWLOCK_SIZE__],
 };
 
+pub const OS_UNFAIR_LOCK_INIT: os_unfair_lock = os_unfair_lock {
+    _os_unfair_lock_opaque: 0,
+};
+
 pub const MINSIGSTKSZ: ::size_t = 32768;
 pub const SIGSTKSZ: ::size_t = 131072;
 
@@ -5221,6 +5253,12 @@ extern "C" {
     pub fn pthread_jit_write_freeze_callbacks_np();
     pub fn pthread_cpu_number_np(cpu_number_out: *mut ::size_t) -> ::c_int;
 
+    pub fn os_unfair_lock_lock(lock: os_unfair_lock_t);
+    pub fn os_unfair_lock_trylock(lock: os_unfair_lock_t) -> bool;
+    pub fn os_unfair_lock_unlock(lock: os_unfair_lock_t);
+    pub fn os_unfair_lock_assert_owner(lock: os_unfair_lock_t);
+    pub fn os_unfair_lock_assert_not_owner(lock: os_unfair_lock_t);
+
     pub fn thread_policy_set(
         thread: thread_t,
         flavor: thread_policy_flavor_t,