diff --git a/esphome/core/scheduler.h b/esphome/core/scheduler.h
index 59a3fece04..5071144691 100644
--- a/esphome/core/scheduler.h
+++ b/esphome/core/scheduler.h
@@ -289,6 +289,12 @@ class Scheduler {
                                       SchedulerItem::Type type, bool match_retry) {
     size_t count = 0;
     for (auto &item : container) {
+      // Skip nullptr items (can happen in defer_queue_ when items are being processed)
+      // The defer_queue_ uses index-based processing: items are std::moved out but left in the
+      // vector as nullptr until cleanup. If cancel_item_locked_() is called from a callback during
+      // defer queue processing, it will iterate over these nullptr items. This check prevents crashes.
+      if (!item)
+        continue;
       if (this->matches_item_(item, component, name_cstr, type, match_retry)) {
         // Mark item for removal (platform-specific)
 #ifdef ESPHOME_THREAD_MULTI_ATOMICS
@@ -311,6 +317,12 @@ class Scheduler {
   bool has_cancelled_timeout_in_container_(const Container &container, Component *component, const char *name_cstr,
                                            bool match_retry) const {
     for (const auto &item : container) {
+      // Skip nullptr items (can happen in defer_queue_ when items are being processed)
+      // The defer_queue_ uses index-based processing: items are std::moved out but left in the
+      // vector as nullptr until cleanup. If this function is called during defer queue processing,
+      // it will iterate over these nullptr items. This check prevents crashes.
+      if (!item)
+        continue;
       if (is_item_removed_(item.get()) &&
           this->matches_item_(item, component, name_cstr, SchedulerItem::TIMEOUT, match_retry,
                               /* skip_removed= */ false)) {