diff --git a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Legacy.h b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Legacy.h
index d5f673d39b6..502c0def5ef 100644
--- a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Legacy.h
+++ b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Legacy.h
@@ -22,8 +22,7 @@ class RuntimeScheduler_Legacy final : public RuntimeSchedulerBase {
  public:
   explicit RuntimeScheduler_Legacy(
       RuntimeExecutor runtimeExecutor,
-      std::function<RuntimeSchedulerTimePoint()> now =
-          RuntimeSchedulerClock::now);
+      std::function<RuntimeSchedulerTimePoint()> now);
 
   /*
    * Not copyable.
diff --git a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Modern.h b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Modern.h
index 372d8c5da19..f730509928b 100644
--- a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Modern.h
+++ b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Modern.h
@@ -23,8 +23,7 @@ class RuntimeScheduler_Modern final : public RuntimeSchedulerBase {
  public:
   explicit RuntimeScheduler_Modern(
       RuntimeExecutor runtimeExecutor,
-      std::function<RuntimeSchedulerTimePoint()> now =
-          RuntimeSchedulerClock::now);
+      std::function<RuntimeSchedulerTimePoint()> now);
 
   /*
    * Not copyable.