diff --git a/esphome/__main__.py b/esphome/__main__.py
index 5e5c9ab556..9a79c0bde2 100644
--- a/esphome/__main__.py
+++ b/esphome/__main__.py
@@ -290,7 +290,7 @@ def upload_using_esptool(config, port, file, speed):
             mcu,
             "write_flash",
             "-z",
-            "--flash_size",
+            "--flash-size",
             "detect",
         ]
         for img in flash_images:
diff --git a/esphome/components/esp32/post_build.py.script b/esphome/components/esp32/post_build.py.script
index 586f12e00b..c995214232 100644
--- a/esphome/components/esp32/post_build.py.script
+++ b/esphome/components/esp32/post_build.py.script
@@ -93,8 +93,8 @@ def merge_factory_bin(source, target, env):
         "esptool",
         "--chip",
         chip,
-        "merge_bin",
-        "--flash_size",
+        "merge-bin",
+        "--flash-size",
         flash_size,
         "--output",
         str(output_path),
@@ -110,7 +110,7 @@ def merge_factory_bin(source, target, env):
     if result == 0:
         print(f"Successfully created {output_path}")
     else:
-        print(f"Error: esptool merge_bin failed with code {result}")
+        print(f"Error: esptool merge-bin failed with code {result}")
 
 
 def esp32_copy_ota_bin(source, target, env):