diff --git a/esphome/components/api/api_connection.cpp b/esphome/components/api/api_connection.cpp
index f2bf3752fa..cd5b3fd694 100644
--- a/esphome/components/api/api_connection.cpp
+++ b/esphome/components/api/api_connection.cpp
@@ -1306,6 +1306,9 @@ void APIConnection::on_voice_assistant_announce_request(const VoiceAssistantAnno
 bool APIConnection::send_voice_assistant_get_configuration_response_(const VoiceAssistantConfigurationRequest &msg) {
   VoiceAssistantConfigurationResponse resp;
   if (!this->check_voice_assistant_api_connection_()) {
+    // send_message encodes synchronously, so this stack local outlives the encode
+    const std::vector<std::string> empty_wake_words;
+    resp.active_wake_words = &empty_wake_words;
     return this->send_message(resp);
   }