diff --git a/esphome/components/voice_assistant/voice_assistant.cpp b/esphome/components/voice_assistant/voice_assistant.cpp
index 7ece73994f..fd35dc7d09 100644
--- a/esphome/components/voice_assistant/voice_assistant.cpp
+++ b/esphome/components/voice_assistant/voice_assistant.cpp
@@ -657,7 +657,8 @@ void VoiceAssistant::on_event(const api::VoiceAssistantEventResponse &msg) {
         ESP_LOGW(TAG, "No text in STT_END event");
         return;
       } else if (text.length() > 500) {
-        text = text.substr(0, 497) + "...";
+        text.resize(497);
+        text += "...";
       }
       ESP_LOGD(TAG, "Speech recognised as: \"%s\"", text.c_str());
       this->defer([this, text]() { this->stt_end_trigger_->trigger(text); });
@@ -714,7 +715,8 @@ void VoiceAssistant::on_event(const api::VoiceAssistantEventResponse &msg) {
         return;
       }
       if (text.length() > 500) {
-        text = text.substr(0, 497) + "...";
+        text.resize(497);
+        text += "...";
       }
       ESP_LOGD(TAG, "Response: \"%s\"", text.c_str());
       this->defer([this, text]() {