diff --git a/litellm/proxy/auth/login_throttle.py b/litellm/proxy/auth/login_throttle.py
index 393411d0670..4ab57ca461f 100644
--- a/litellm/proxy/auth/login_throttle.py
+++ b/litellm/proxy/auth/login_throttle.py
@@ -137,10 +137,14 @@ def _int_setting(settings: Mapping[str, object], key: str, default: int) -> int:
 
 
 def _parse_address(client_ip: str) -> ipaddress.IPv4Address | ipaddress.IPv6Address | None:
+    """The address as it is limited and counted: an IPv4-mapped IPv6 address is its IPv4 address."""
     try:
-        return ipaddress.ip_address(client_ip)
+        address: Final = ipaddress.ip_address(client_ip)
     except ValueError:
         return None
+    if isinstance(address, ipaddress.IPv6Address) and address.ipv4_mapped is not None:
+        return address.ipv4_mapped
+    return address
 
 
 def _parse_network(raw_range: str) -> _Network | None:
@@ -183,9 +187,6 @@ def source_group(client_ip: str) -> str:
     if address is None:
         return client_ip
     if isinstance(address, ipaddress.IPv6Address):
-        mapped: Final = address.ipv4_mapped
-        if mapped is not None:
-            return str(mapped)
         return str(ipaddress.ip_network((address, IPV6_SOURCE_PREFIX_LENGTH), strict=False))
     return str(address)
 
diff --git a/tests/test_litellm/proxy/auth/test_login_utils.py b/tests/test_litellm/proxy/auth/test_login_utils.py
index 65c388240e5..df5bd29f8ff 100644
--- a/tests/test_litellm/proxy/auth/test_login_utils.py
+++ b/tests/test_litellm/proxy/auth/test_login_utils.py
@@ -955,6 +955,8 @@ def test_source_overrides_pick_the_most_specific_matching_range():
     assert _limit("203.0.1.1") == 100
     assert _limit("192.0.2.1") == 7
     assert _limit("198.51.100.1") == 7, "a garbage limit falls back to the default rather than a huge or zero budget"
+    assert _limit("::ffff:203.0.113.9") == 300, "a mapped address gets the limit of the IPv4 bucket it is counted in"
+    assert _limit("::ffff:203.0.113.10") == 200
 
 
 def test_ipv6_sources_are_grouped_by_their_64_bit_prefix():