diff --git a/src/mcp/shared/version.py b/src/mcp/shared/version.py
index 23c46d04be..d2a1e462d4 100644
--- a/src/mcp/shared/version.py
+++ b/src/mcp/shared/version.py
@@ -1,3 +1,3 @@
 from mcp.types import LATEST_PROTOCOL_VERSION
 
-SUPPORTED_PROTOCOL_VERSIONS: list[str] = ["2024-11-05", "2025-03-26", LATEST_PROTOCOL_VERSION]
+SUPPORTED_PROTOCOL_VERSIONS: list[str] = ["2024-11-05", "2025-03-26", "2025-06-18", LATEST_PROTOCOL_VERSION]
diff --git a/src/mcp/types.py b/src/mcp/types.py
index 7a46ad6201..9ca8ffc188 100644
--- a/src/mcp/types.py
+++ b/src/mcp/types.py
@@ -24,7 +24,7 @@
   not separate types in the schema.
 """
 
-LATEST_PROTOCOL_VERSION = "2025-06-18"
+LATEST_PROTOCOL_VERSION = "2025-11-25"
 
 """
 The default negotiated version of the Model Context Protocol when no version is specified.
diff --git a/tests/issues/test_1027_win_unreachable_cleanup.py b/tests/issues/test_1027_win_unreachable_cleanup.py
index 999bb9eadf..63d6dd8dcf 100644
--- a/tests/issues/test_1027_win_unreachable_cleanup.py
+++ b/tests/issues/test_1027_win_unreachable_cleanup.py
@@ -95,7 +95,7 @@ def echo(text: str) -> str:
             async with ClientSession(read, write) as session:
                 # Initialize the session
                 result = await session.initialize()
-                assert result.protocolVersion in ["2024-11-05", "2025-06-18"]
+                assert result.protocolVersion in ["2024-11-05", "2025-06-18", "2025-11-25"]
 
                 # Verify startup marker was created
                 assert Path(startup_marker).exists(), "Server startup marker not created"