diff --git a/pw_sync_zephyr/public/pw_sync_zephyr/interrupt_spin_lock_inline.h b/pw_sync_zephyr/public/pw_sync_zephyr/interrupt_spin_lock_inline.h
index 558caf41bb..c98f6d9ad2 100644
--- a/pw_sync_zephyr/public/pw_sync_zephyr/interrupt_spin_lock_inline.h
+++ b/pw_sync_zephyr/public/pw_sync_zephyr/interrupt_spin_lock_inline.h
@@ -18,7 +18,7 @@
 namespace pw::sync {
 
 constexpr InterruptSpinLock::InterruptSpinLock()
-    : native_type_{.lock = {0}, .locked = false, .key = {0}} {}
+    : native_type_{.lock = {}, .locked = false, .key = {0}} {}
 
 inline bool InterruptSpinLock::try_lock() {
   // This backend will spin the current processor until the deadlock is