diff --git a/src/fastmcp/server/server.py b/src/fastmcp/server/server.py
index 0d77d26a5..e4af96c37 100644
--- a/src/fastmcp/server/server.py
+++ b/src/fastmcp/server/server.py
@@ -345,7 +345,7 @@ async def run_async(
             transport: Transport protocol to use ("stdio", "sse", or "streamable-http")
         """
         if transport is None:
-            transport = "stdio"
+            transport = self._deprecated_settings.transport
         if transport not in {"stdio", "http", "sse", "streamable-http"}:
             raise ValueError(f"Unknown transport: {transport}")
 
diff --git a/src/fastmcp/settings.py b/src/fastmcp/settings.py
index 5cbc8dfad..d9184d3f0 100644
--- a/src/fastmcp/settings.py
+++ b/src/fastmcp/settings.py
@@ -22,6 +22,7 @@
 LOG_LEVEL = Literal["DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"]
 
 DuplicateBehavior = Literal["warn", "error", "replace", "ignore"]
+Transport = Literal["stdio", "http", "sse", "streamable-http"]
 
 
 class ExtendedEnvSettingsSource(EnvSettingsSource):
@@ -220,6 +221,14 @@ def normalize_log_level(cls, v):
         ),
     ] = None
 
+    transport: Annotated[
+        Transport,
+        Field(
+            default="stdio",
+            description="The transport protocol to use for the server. Defaults to 'stdio'.",
+        ),
+    ] = "stdio"
+
     # HTTP settings
     host: str = "127.0.0.1"
     port: int = 8000