diff --git a/esphome/config_validation.py b/esphome/config_validation.py
index 0a6b2dfbb0..cf0b1d3aca 100644
--- a/esphome/config_validation.py
+++ b/esphome/config_validation.py
@@ -108,6 +108,7 @@ ROOT_CONFIG_PATH = object()
 
 RESERVED_IDS = [
     # C++ keywords http://en.cppreference.com/w/cpp/keyword
+    "alarm",
     "alignas",
     "alignof",
     "and",