diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp
index 2adda076f4..549734d974 100644
--- a/esphome/core/helpers.cpp
+++ b/esphome/core/helpers.cpp
@@ -282,7 +282,7 @@ std::string str_sanitize(const std::string &str) {
   std::replace_if(
       str.begin(), str.end(),
       [](const char &c) {
-        return c == '-' || c == '_' || (c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
+        return !(c == '-' || c == '_' || (c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'));
       },
       '_');
   return out;