diff --git a/litellm/constants.py b/litellm/constants.py
index 23e92d26a59..57b8abd9553 100644
--- a/litellm/constants.py
+++ b/litellm/constants.py
@@ -400,10 +400,10 @@ MAX_STRING_LENGTH_PROMPT_IN_DB: Final = int(os.getenv("MAX_STRING_LENGTH_PROMPT_
 BEDROCK_MAX_POLICY_SIZE: Final = int(os.getenv("BEDROCK_MAX_POLICY_SIZE", 75))
 # One entry per distinct AWS credential-argument set. Per-user cost attribution passes the attributed
 # identity as aws_session_name, so this bounds how many attributed identities keep a cached STS session.
-BEDROCK_IAM_CACHE_MAX_ENTRIES: Final = 1000
+BEDROCK_IAM_CACHE_MAX_ENTRIES: Final = int(os.getenv("BEDROCK_IAM_CACHE_MAX_ENTRIES", "1000"))
 # Single-flight lock stripes over that cache. Only keys landing on the same stripe wait for each
 # other, so a burst of distinct identities still resolves its credentials in parallel.
-BEDROCK_IAM_CACHE_FETCH_LOCK_STRIPES: Final = 64
+BEDROCK_IAM_CACHE_FETCH_LOCK_STRIPES: Final = int(os.getenv("BEDROCK_IAM_CACHE_FETCH_LOCK_STRIPES", "64"))
 # Retire a cached STS credential this many seconds before AWS expires it, so a request that reads it
 # still has a usable credential for the whole call.
 STS_CREDENTIAL_EXPIRY_SAFETY_MARGIN_SECONDS: Final = 60
diff --git a/tests/test_litellm/test_constants.py b/tests/test_litellm/test_constants.py
index 12e473f68a4..0ae9f150269 100644
--- a/tests/test_litellm/test_constants.py
+++ b/tests/test_litellm/test_constants.py
@@ -68,3 +68,36 @@ def _build_constant_env_var_map() -> dict[str, str]:
             env_var_map[constant_name] = env_var_name
 
     return env_var_map
+
+
+@pytest.mark.parametrize(
+    "constant_name, override",
+    [
+        ("BEDROCK_IAM_CACHE_MAX_ENTRIES", 4096),
+        ("BEDROCK_IAM_CACHE_FETCH_LOCK_STRIPES", 128),
+    ],
+)
+def test_bedrock_iam_cache_bounds_are_env_overridable(constant_name: str, override: int) -> None:
+    try:
+        with mock.patch.dict(os.environ, {constant_name: str(override)}):
+            reloaded = importlib.reload(constants)
+            assert getattr(reloaded, constant_name) == override
+    finally:
+        importlib.reload(constants)
+
+
+@pytest.mark.parametrize(
+    "constant_name, expected_default",
+    [
+        ("BEDROCK_IAM_CACHE_MAX_ENTRIES", 1000),
+        ("BEDROCK_IAM_CACHE_FETCH_LOCK_STRIPES", 64),
+    ],
+)
+def test_bedrock_iam_cache_bounds_keep_their_defaults(constant_name: str, expected_default: int) -> None:
+    try:
+        with mock.patch.dict(os.environ, {}, clear=False):
+            os.environ.pop(constant_name, None)
+            reloaded = importlib.reload(constants)
+            assert getattr(reloaded, constant_name) == expected_default
+    finally:
+        importlib.reload(constants)