diff --git a/pyproject.toml b/pyproject.toml
index 02834f604d2..a9099f5baea 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -73,6 +73,10 @@ proxy = [
     "hiredis>=3.0.0,<4.0; python_version < '3.15'",
     "hiredis>=3.5.0,<4.0; python_version >= '3.15'",
     "apscheduler>=3.11.2,<4.0",
+    # zoneinfo fallback tz database. The OS db drops legacy IANA aliases (Asia/Calcutta on
+    # Ubuntu 24.04+ needs the separate tzdata-legacy package), so proxy startup without the
+    # wheel dies with ZoneInfoNotFoundError. Ref: BerriAI/litellm#49813.
+    "tzdata>=2024.1",
     "fastapi-sso>=0.19.0,<1.0",
     "PyJWT>=2.13.0,<3.0",
     "python-multipart>=0.0.27,<1.0",
diff --git a/tests/unit/test_proxy_extra_tzdata.py b/tests/unit/test_proxy_extra_tzdata.py
new file mode 100644
index 00000000000..ccdd99e1603
--- /dev/null
+++ b/tests/unit/test_proxy_extra_tzdata.py
@@ -0,0 +1,37 @@
+"""
+Static checks that the `proxy` extra ships tzdata.
+
+Legacy IANA aliases such as `Asia/Calcutta` are absent from the OS zone database
+on stock Ubuntu 24.04+ (they moved to the separate `tzdata-legacy` package).
+zoneinfo then falls back to the `tzdata` wheel, and `pip install litellm[proxy]`
+without it exits at proxy startup with
+`ZoneInfoNotFoundError: 'tzlocal() does not support non-zoneinfo timezones like
+Asia/Calcutta. Please use a timezone in the form of Continent/City'`
+(BerriAI/litellm#49813). The Docker images install the OS `tzdata` apk package,
+so only the pip surface regresses when this extra loses the wheel
+"""
+
+import sys
+from pathlib import Path
+from typing import Final
+
+from packaging.requirements import Requirement
+
+if sys.version_info >= (3, 11):
+    import tomllib
+else:
+    import tomli as tomllib
+
+PYPROJECT: Final = Path(__file__).resolve().parents[2] / "pyproject.toml"
+
+
+def test_proxy_extra_requires_tzdata_on_all_platforms() -> None:
+    manifest: Final = tomllib.loads(PYPROJECT.read_text())
+    proxy_specs: Final = tuple(Requirement(spec) for spec in manifest["project"]["optional-dependencies"]["proxy"])
+    tzdata_specs: Final = tuple(spec for spec in proxy_specs if spec.name == "tzdata")
+    assert len(tzdata_specs) == 1, (
+        "pip install litellm[proxy] must ship tzdata: proxy startup with a legacy IANA alias like "
+        f"TZ=Asia/Calcutta dies with ZoneInfoNotFoundError without it, got specs {proxy_specs}"
+    )
+    marker: Final = tzdata_specs[0].marker
+    assert marker is None, f"tzdata is required on every platform the proxy starts on, found marker {marker}"
diff --git a/uv.lock b/uv.lock
index 8712b78bbd6..6a8d012fb5b 100644
--- a/uv.lock
+++ b/uv.lock
@@ -5125,6 +5125,7 @@ proxy = [
     { name = "soundfile" },
     { name = "starlette" },
     { name = "tomlkit" },
+    { name = "tzdata" },
     { name = "uvicorn" },
     { name = "uvloop", marker = "sys_platform != 'win32'" },
     { name = "websockets" },
@@ -5408,6 +5409,7 @@ requires-dist = [
     { name = "tomlkit", marker = "extra == 'cli'", specifier = ">=0.13.3,<1.0" },
     { name = "tomlkit", marker = "extra == 'proxy'", specifier = ">=0.13.3,<1.0" },
     { name = "typing-extensions", specifier = ">=4.13.0,<5.0" },
+    { name = "tzdata", marker = "extra == 'proxy'", specifier = ">=2024.1" },
     { name = "uvicorn", marker = "extra == 'proxy'", specifier = ">=0.33.0,<1.0" },
     { name = "uvloop", marker = "sys_platform != 'win32' and extra == 'proxy'", specifier = ">=0.22.1,<1.0" },
     { name = "websockets", marker = "extra == 'proxy'", specifier = ">=15.0.1,<16.0" },