diff --git a/include/ruby/thread_native.h b/include/ruby/thread_native.h
index c23b15e133..8217a67514 100644
--- a/include/ruby/thread_native.h
+++ b/include/ruby/thread_native.h
@@ -28,6 +28,11 @@ typedef union rb_thread_lock_union {
     CRITICAL_SECTION crit;
 } rb_nativethread_lock_t;
 
+struct rb_thread_cond_struct {
+    struct cond_event_entry *next;
+    struct cond_event_entry *prev;
+};
+
 typedef struct rb_thread_cond_struct rb_nativethread_cond_t;
 
 #elif defined(HAVE_PTHREAD_H)
diff --git a/thread_win32.h b/thread_win32.h
index f00f3b2056..0dfe9d46de 100644
--- a/thread_win32.h
+++ b/thread_win32.h
@@ -21,11 +21,6 @@
 WINBASEAPI BOOL WINAPI
 TryEnterCriticalSection(IN OUT LPCRITICAL_SECTION lpCriticalSection);
 
-struct rb_thread_cond_struct {
-    struct cond_event_entry *next;
-    struct cond_event_entry *prev;
-};
-
 struct rb_native_thread {
     HANDLE thread_id;
     HANDLE interrupt_event;