diff --git a/homeassistant/components/telegram_bot/config_flow.py b/homeassistant/components/telegram_bot/config_flow.py
index 7b441889b8c..b6480b84f64 100644
--- a/homeassistant/components/telegram_bot/config_flow.py
+++ b/homeassistant/components/telegram_bot/config_flow.py
@@ -328,6 +328,9 @@ class TelgramBotConfigFlow(ConfigFlow, domain=DOMAIN):
 
         # validate connection to Telegram API
         errors: dict[str, str] = {}
+        user_input[CONF_PROXY_URL] = user_input[SECTION_ADVANCED_SETTINGS].get(
+            CONF_PROXY_URL
+        )
         bot_name = await self._validate_bot(
             user_input, errors, description_placeholders
         )
@@ -350,7 +353,9 @@ class TelgramBotConfigFlow(ConfigFlow, domain=DOMAIN):
                 data={
                     CONF_PLATFORM: user_input[CONF_PLATFORM],
                     CONF_API_KEY: user_input[CONF_API_KEY],
-                    CONF_PROXY_URL: user_input["advanced_settings"].get(CONF_PROXY_URL),
+                    CONF_PROXY_URL: user_input[SECTION_ADVANCED_SETTINGS].get(
+                        CONF_PROXY_URL
+                    ),
                 },
                 options={
                     # this value may come from yaml import
diff --git a/tests/components/telegram_bot/test_config_flow.py b/tests/components/telegram_bot/test_config_flow.py
index 2af90b9f7ef..659effdda7b 100644
--- a/tests/components/telegram_bot/test_config_flow.py
+++ b/tests/components/telegram_bot/test_config_flow.py
@@ -117,6 +117,7 @@ async def test_reconfigure_flow_broadcast(
     assert result["type"] is FlowResultType.ABORT
     assert result["reason"] == "reconfigure_successful"
     assert mock_webhooks_config_entry.data[CONF_PLATFORM] == PLATFORM_BROADCAST
+    assert mock_webhooks_config_entry.data[CONF_PROXY_URL] == "https://test"
 
 
 async def test_reconfigure_flow_webhooks(