diff --git a/esphome/core/application.h b/esphome/core/application.h
index e9c8638f60..aeda245161 100644
--- a/esphome/core/application.h
+++ b/esphome/core/application.h
@@ -39,7 +39,7 @@ class Application {
  public:
   void pre_setup(const std::string &name, const char *compilation_time, bool name_add_mac_suffix) {
     if (name_add_mac_suffix) {
-      this->name_ = name + "_" + get_mac_address().substr(6);
+      this->name_ = name + "-" + get_mac_address().substr(6);
     } else {
       this->name_ = name;
     }