diff --git a/esphome/core/scheduler.h b/esphome/core/scheduler.h
index 56fc83f12f..4911bdde74 100644
--- a/esphome/core/scheduler.h
+++ b/esphome/core/scheduler.h
@@ -518,7 +518,8 @@ class Scheduler {
                                                                             uint32_t hash_or_id,
                                                                             SchedulerItem::Type type, bool find_first);
 
-  Mutex lock_;
+  // Empty on single-threaded platforms (ESP8266, RP2), so it takes no space there
+  [[no_unique_address]] Mutex lock_;
   std::vector<SchedulerItem *> items_;
   std::vector<SchedulerItem *> to_add_;