diff --git a/litellm/proxy/common_utils/banner.py b/litellm/proxy/common_utils/banner.py
index 25ad5e295f6..6926f3f013b 100644
--- a/litellm/proxy/common_utils/banner.py
+++ b/litellm/proxy/common_utils/banner.py
@@ -1,6 +1,6 @@
+import sys
 from typing import Final
 
-# LiteLLM ASCII banner
 LITELLM_BANNER: Final = """   ██╗     ██╗████████╗███████╗██╗     ██╗     ███╗   ███╗
    ██║     ██║╚══██╔══╝██╔════╝██║     ██║     ████╗ ████║
    ██║     ██║   ██║   █████╗  ██║     ██║     ██╔████╔██║
@@ -8,12 +8,38 @@ LITELLM_BANNER: Final = """   ██╗     ██╗████████╗
    ███████╗██║   ██║   ███████╗███████╗███████╗██║ ╚═╝ ██║
    ╚══════╝╚═╝   ╚═╝   ╚══════╝╚══════╝╚══════╝╚═╝     ╚═╝"""
 
+LITELLM_BANNER_ASCII: Final = r"""    _       _____  _______  ______  _       _       __  __
+   | |     |_   _||__   __||  ____|| |     | |     |  \/  |
+   | |       | |     | |   | |__   | |     | |     | \  / |
+   | |       | |     | |   |  __|  | |     | |     | |\/| |
+   | |____  _| |_    | |   | |____ | |____ | |____ | |  | |
+   |______||_____|   |_|   |______||______||______||_|  |_|"""
 
-def show_banner():
-    """Display the LiteLLM CLI banner."""
+
+def banner_for_encoding(encoding: str | None) -> str:
+    """Return the banner variant that ``encoding`` can represent."""
+    if encoding is None:
+        return LITELLM_BANNER
+    try:
+        LITELLM_BANNER.encode(encoding)
+    except (UnicodeEncodeError, LookupError):
+        return LITELLM_BANNER_ASCII
+    return LITELLM_BANNER
+
+
+def _echo(text: str) -> None:
     try:
         import click
 
-        click.echo(f"\n{LITELLM_BANNER}\n")
+        click.echo(text)
     except ImportError:
-        print("\n")  # noqa: T201
+        print(text)  # noqa: T201  # the banner is CLI output, and click is what we would print through
+
+
+def show_banner() -> None:
+    """Display the LiteLLM CLI banner. Never raises: the banner must not block startup."""
+    encoding: Final[str | None] = getattr(sys.stdout, "encoding", None)
+    try:
+        _echo(f"\n{banner_for_encoding(encoding)}\n")
+    except UnicodeEncodeError:
+        pass
diff --git a/tests/test_litellm/proxy/common_utils/test_banner.py b/tests/test_litellm/proxy/common_utils/test_banner.py
new file mode 100644
index 00000000000..9f2f96db82b
--- /dev/null
+++ b/tests/test_litellm/proxy/common_utils/test_banner.py
@@ -0,0 +1,61 @@
+from contextlib import redirect_stdout
+from pathlib import Path
+
+import pytest
+
+from litellm.proxy.common_utils.banner import (
+    LITELLM_BANNER,
+    LITELLM_BANNER_ASCII,
+    banner_for_encoding,
+    show_banner,
+)
+
+
+def _banner_written_to_stdout(encoding: str, destination: Path) -> str:
+    with destination.open("w", encoding=encoding, errors="strict") as stream, redirect_stdout(stream):
+        show_banner()
+    return destination.read_text(encoding=encoding)
+
+
+@pytest.mark.parametrize("encoding", ["utf-8", "utf-16", "cp1252", "cp437", "cp850", "ascii", "latin-1", "koi8-r"])
+def test_banner_for_encoding_returns_a_banner_the_encoding_can_represent(encoding: str):
+    """
+    The banner we hand to stdout must always survive that stream's codec.
+
+    Regression for the proxy exiting at startup on Windows when stdout is redirected:
+    the ANSI code page there is cp1252, which has none of the box-drawing characters
+    the unicode banner is drawn with.
+    """
+    assert banner_for_encoding(encoding).encode(encoding)
+
+
+def test_banner_for_encoding_prefers_the_unicode_banner_when_the_codec_allows_it():
+    assert banner_for_encoding("utf-8") == LITELLM_BANNER
+
+
+def test_banner_for_encoding_degrades_when_the_codec_cannot_represent_the_unicode_banner():
+    assert banner_for_encoding("cp1252") == LITELLM_BANNER_ASCII
+
+
+def test_banner_for_encoding_degrades_for_a_codec_python_does_not_know():
+    assert banner_for_encoding("not-a-real-codec") == LITELLM_BANNER_ASCII
+
+
+def test_banner_for_encoding_keeps_the_unicode_banner_when_the_stream_has_no_encoding():
+    assert banner_for_encoding(None) == LITELLM_BANNER
+
+
+def test_show_banner_does_not_raise_when_stdout_cannot_encode_the_unicode_banner(tmp_path: Path):
+    """
+    show_banner() runs as the first statement of run_server, so anything it raises takes
+    the whole proxy down before it binds a port.
+    """
+    written = _banner_written_to_stdout("cp1252", tmp_path / "stdout.log")
+
+    assert LITELLM_BANNER_ASCII in written
+
+
+def test_show_banner_still_writes_the_unicode_banner_to_a_utf8_stdout(tmp_path: Path):
+    written = _banner_written_to_stdout("utf-8", tmp_path / "stdout.log")
+
+    assert LITELLM_BANNER in written