diff --git a/pybaseball/retrosheet.py b/pybaseball/retrosheet.py
index 391f55bb..7063900c 100644
--- a/pybaseball/retrosheet.py
+++ b/pybaseball/retrosheet.py
@@ -24,7 +24,7 @@
 from pybaseball.utils import get_text_file
 from datetime import datetime
 from io import StringIO
-from github import Github
+from github import Auth, Github
 import os
 from getpass import getuser, getpass
 from github.GithubException import RateLimitExceededException
@@ -131,7 +131,7 @@ def events(season, type='regular', export_dir='.'):
                            "the valid types are: 'regular', 'post', and 'asg'.")
 
     try:
-        g = Github(GH_TOKEN)
+        g = Github(auth=Auth.Token(GH_TOKEN)) if GH_TOKEN else Github()
         repo = g.get_repo('chadwickbureau/retrosheet')
         season_folder = [f.path[f.path.rfind('/')+1:] for f in repo.get_contents(f'seasons/{season}')]
         season_events = [t for t in season_folder if t.endswith(file_extension)]
@@ -156,7 +156,7 @@ def rosters(season):
     GH_TOKEN=os.getenv('GH_TOKEN', '')
 
     try:
-        g = Github(GH_TOKEN)
+        g = Github(auth=Auth.Token(GH_TOKEN)) if GH_TOKEN else Github()
         repo = g.get_repo('chadwickbureau/retrosheet')
         season_folder = [f.path[f.path.rfind('/')+1:] for f in repo.get_contents(f'seasons/{season}')]
         rosters = [t for t in season_folder if t.endswith('.ROS')]
@@ -179,7 +179,7 @@ def _roster(team, season, checked = False):
     GH_TOKEN=os.getenv('GH_TOKEN', '')
 
     if not checked:
-        g = Github(GH_TOKEN)
+        g = Github(auth=Auth.Token(GH_TOKEN)) if GH_TOKEN else Github()
         try:
             repo = g.get_repo('chadwickbureau/retrosheet')
             season_folder = [f.path[f.path.rfind('/')+1:] for f in repo.get_contents(f'seasons/{season}')]
@@ -213,7 +213,7 @@ def schedules(season):
     """
     GH_TOKEN=os.getenv('GH_TOKEN', '')
     # validate input
-    g = Github(GH_TOKEN)
+    g = Github(auth=Auth.Token(GH_TOKEN)) if GH_TOKEN else Github()
     repo = g.get_repo('chadwickbureau/retrosheet')
     season_folder = [f.path[f.path.rfind('/')+1:] for f in repo.get_contents(f'seasons/{season}')]
     file_name = f'{season}schedule.csv'
@@ -231,7 +231,7 @@ def season_game_logs(season):
     """
     GH_TOKEN=os.getenv('GH_TOKEN', '')
     # validate input
-    g = Github(GH_TOKEN)
+    g = Github(auth=Auth.Token(GH_TOKEN)) if GH_TOKEN else Github()
     repo = g.get_repo('chadwickbureau/retrosheet')
     season_folder = [f.path[f.path.rfind('/')+1:] for f in repo.get_contents(f'seasons/{season}')]
     gamelog_file_name = f'GL{season}.TXT'
diff --git a/tests/pybaseball/test_retrosheet.py b/tests/pybaseball/test_retrosheet.py
new file mode 100644
index 00000000..3604ee78
--- /dev/null
+++ b/tests/pybaseball/test_retrosheet.py
@@ -0,0 +1,38 @@
+from unittest.mock import MagicMock
+
+import pytest
+
+import pybaseball.retrosheet as retrosheet
+
+
+def test_events_uses_token_auth(monkeypatch: pytest.MonkeyPatch) -> None:
+    # Regression test for #455: when GH_TOKEN is set, the GitHub client must be
+    # built with the modern keyword auth API (Auth.Token) rather than the
+    # deprecated positional-token form.
+    monkeypatch.setenv('GH_TOKEN', 'dummy_token')
+    fake_github = MagicMock()
+    fake_github.return_value.get_repo.side_effect = RuntimeError("stop")
+    monkeypatch.setattr(retrosheet, 'Github', fake_github)
+
+    with pytest.raises(RuntimeError):
+        retrosheet.events(2019)
+
+    args, kwargs = fake_github.call_args
+    assert args == ()
+    assert 'auth' in kwargs
+
+
+def test_events_anonymous_without_token(monkeypatch: pytest.MonkeyPatch) -> None:
+    # Regression test for #455: with no GH_TOKEN, the client must be created
+    # anonymously (Github()) instead of passing an empty token string.
+    monkeypatch.delenv('GH_TOKEN', raising=False)
+    fake_github = MagicMock()
+    fake_github.return_value.get_repo.side_effect = RuntimeError("stop")
+    monkeypatch.setattr(retrosheet, 'Github', fake_github)
+
+    with pytest.raises(RuntimeError):
+        retrosheet.events(2019)
+
+    args, kwargs = fake_github.call_args
+    assert args == ()
+    assert 'auth' not in kwargs