diff --git a/esphome/components/uptime/text_sensor/uptime_text_sensor.cpp b/esphome/components/uptime/text_sensor/uptime_text_sensor.cpp
index f9caa1641b..51b85b9e96 100644
--- a/esphome/components/uptime/text_sensor/uptime_text_sensor.cpp
+++ b/esphome/components/uptime/text_sensor/uptime_text_sensor.cpp
@@ -16,7 +16,7 @@ void UptimeTextSensor::setup() {
   this->update();
 }
 
-void UptimeTextSensor::insert_buffer(std::string &buffer, const char *key, unsigned value) const {
+void UptimeTextSensor::insert_buffer_(std::string &buffer, const char *key, unsigned value) const {
   if (!buffer.empty() && !this->separator_.empty())
     buffer.insert(0, this->separator_);
   buffer.insert(0, str_sprintf("%u%s", value, key));
@@ -38,25 +38,25 @@ void UptimeTextSensor::update() {
     unsigned remainder = uptime % 60;
     uptime /= 60;
     if (interval < 30) {
-      insert_buffer(buffer, "s", remainder);
+      this->insert_buffer_(buffer, "s", remainder);
       if (uptime == 0)
         break;
     }
     remainder = uptime % 60;
     uptime /= 60;
     if (interval < 1800) {
-      insert_buffer(buffer, "m", remainder);
+      this->insert_buffer_(buffer, "m", remainder);
       if (uptime == 0)
         break;
     }
     remainder = uptime % 24;
     uptime /= 24;
     if (interval < 12 * 3600) {
-      insert_buffer(buffer, "h", remainder);
+      this->insert_buffer_(buffer, "h", remainder);
       if (uptime == 0)
         break;
     }
-    insert_buffer(buffer, "d", (unsigned) uptime);
+    this->insert_buffer_(buffer, "d", (unsigned) uptime);
     break;
   }
   this->publish_state(buffer);
diff --git a/esphome/components/uptime/text_sensor/uptime_text_sensor.h b/esphome/components/uptime/text_sensor/uptime_text_sensor.h
index 72be0b6c6f..51cf629ae4 100644
--- a/esphome/components/uptime/text_sensor/uptime_text_sensor.h
+++ b/esphome/components/uptime/text_sensor/uptime_text_sensor.h
@@ -13,13 +13,13 @@ class UptimeTextSensor : public text_sensor::TextSensor, public PollingComponent
   void update() override;
   void dump_config() override;
   void setup() override;
-  void insert_buffer(std::string &buffer, const char *key, unsigned value) const;
 
   void set_separator(const std::string &separator) { this->separator_ = separator; }
 
   float get_setup_priority() const override;
 
  protected:
+  void insert_buffer_(std::string &buffer, const char *key, unsigned value) const;
   std::string separator_{};
   uint32_t uptime_{0};  // uptime in seconds, will overflow after 136 years
   uint32_t last_ms_{0};