diff --git a/esphome/components/esphome/ota/__init__.py b/esphome/components/esphome/ota/__init__.py
index f2c37155ae..89bbd5ebac 100644
--- a/esphome/components/esphome/ota/__init__.py
+++ b/esphome/components/esphome/ota/__init__.py
@@ -129,6 +129,20 @@ def ota_esphome_final_validate(config: ConfigType) -> None:
         _validate_no_password_with_encryption(ota_conf)
         if (encryption_conf := ota_conf.get(CONF_ENCRYPTION)) is not None:
             _resolve_encryption_key(encryption_conf, api_conf)
+        elif CONF_PASSWORD in ota_conf and _api_static_key(api_conf) is not None:
+            _LOGGER.warning(
+                "The '%s' %s %s also authenticates OTA uploads and encrypts them, "
+                "so '%s' %s only guards plaintext uploads; remove '%s' and add "
+                "'%s' under '%s' to require encryption",
+                CONF_API,
+                CONF_ENCRYPTION,
+                CONF_KEY,
+                CONF_OTA,
+                CONF_PASSWORD,
+                CONF_PASSWORD,
+                CONF_ENCRYPTION,
+                CONF_OTA,
+            )
     if any(
         conf.get(CONF_PLATFORM) == CONF_WEB_SERVER for conf in full_ota_conf
     ) and any(
diff --git a/tests/component_tests/ota/test_esphome_ota.py b/tests/component_tests/ota/test_esphome_ota.py
index b3c01636c6..d4a0911ec7 100644
--- a/tests/component_tests/ota/test_esphome_ota.py
+++ b/tests/component_tests/ota/test_esphome_ota.py
@@ -346,6 +346,44 @@ def test_encryption_with_captive_portal_web_server_ota_warns(
         fv.full_config.reset(token)
 
 
+def test_password_with_api_key_warns(caplog: pytest.LogCaptureFixture) -> None:
+    """An api key makes the device offer encryption, which authenticates an
+    uploader without the password; the config validates with a warning."""
+    full_conf = {
+        CONF_API: {CONF_ENCRYPTION: {CONF_KEY: API_KEY}},
+        CONF_OTA: [_make_ota_config(port=3232, **{CONF_PASSWORD: "pw"})],
+    }
+    token = fv.full_config.set(full_conf)
+    try:
+        with caplog.at_level(logging.WARNING):
+            ota_esphome_final_validate({})
+        assert any("only guards plaintext" in r.message for r in caplog.records)
+    finally:
+        fv.full_config.reset(token)
+
+
+@pytest.mark.parametrize(
+    "api_conf",
+    [{}, {CONF_ENCRYPTION: {}}, {CONF_ENCRYPTION: {CONF_KEY: ZEROS_KEY}}],
+    ids=["no_api", "runtime_key", "zeros_key"],
+)
+def test_password_without_static_api_key_no_warning(
+    caplog: pytest.LogCaptureFixture, api_conf: dict[str, Any]
+) -> None:
+    """Without a build-time api key there is no offer, so nothing to warn about."""
+    full_conf = {
+        CONF_API: api_conf,
+        CONF_OTA: [_make_ota_config(port=3232, **{CONF_PASSWORD: "pw"})],
+    }
+    token = fv.full_config.set(full_conf)
+    try:
+        with caplog.at_level(logging.WARNING):
+            ota_esphome_final_validate({})
+        assert not any("only guards plaintext" in r.message for r in caplog.records)
+    finally:
+        fv.full_config.reset(token)
+
+
 def test_web_server_ota_without_encryption_unaffected() -> None:
     """web_server ota stays valid alongside an unencrypted esphome entry."""
     full_conf = {