diff --git a/esphome/components/web_server_idf/web_server_idf.cpp b/esphome/components/web_server_idf/web_server_idf.cpp
index a78daf4790..d2447681f5 100644
--- a/esphome/components/web_server_idf/web_server_idf.cpp
+++ b/esphome/components/web_server_idf/web_server_idf.cpp
@@ -39,8 +39,10 @@ static const char *const TAG = "web_server_idf";
 
 // Global instance to avoid guard variable (saves 8 bytes)
 // This is initialized at program startup before any threads
+namespace {
 // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
-static DefaultHeaders default_headers_instance;
+DefaultHeaders default_headers_instance;
+}  // namespace
 
 DefaultHeaders &DefaultHeaders::Instance() { return default_headers_instance; }