diff --git a/src/workos/_base_client.py b/src/workos/_base_client.py
index 7c6f7e64..15c5f4c1 100644
--- a/src/workos/_base_client.py
+++ b/src/workos/_base_client.py
@@ -3,6 +3,7 @@
 
 import asyncio
 import json
+import math
 import os
 import platform
 import time
@@ -49,6 +50,10 @@
 INITIAL_RETRY_DELAY = 1
 MAX_RETRY_DELAY = 30
 RETRY_MULTIPLIER = 2
+# Upper bound on a server-provided Retry-After sleep, in seconds. Matches the
+# Node SDK so an aggressive proxy or a far-future HTTP-date cannot stall the
+# caller. The raw header value is still reported on RateLimitExceededError.
+MAX_RETRY_AFTER = 60
 
 
 # Segments that URL normalization treats structurally; never valid identifiers.
@@ -129,16 +134,24 @@ def build_url(
 
     @staticmethod
     def _parse_retry_after(retry_after: Optional[str]) -> Optional[float]:
-        """Parse Retry-After as seconds or an HTTP-date."""
+        """Parse Retry-After as RFC 9110 delay-seconds or an HTTP-date.
+
+        Returns ``None`` for absent or unparseable values so callers fall back
+        to exponential backoff. Delay-seconds must be a plain non-negative
+        integer, which rejects forms ``float()`` would otherwise accept such as
+        ``NaN``, ``Infinity`` or ``1e309``. The result is not capped here so
+        :class:`RateLimitExceededError` reports what the server actually sent;
+        :meth:`_calculate_retry_delay` bounds the sleep.
+        """
         if not retry_after:
             return None
         value = retry_after.strip()
         if not value:
             return None
-        try:
-            return max(float(value), 0.0)
-        except ValueError:
-            pass
+        if value.isdecimal():
+            seconds = float(value)
+            # A digit string long enough to overflow float parses as inf.
+            return seconds if math.isfinite(seconds) else None
         try:
             retry_at = parsedate_to_datetime(value)
         except (TypeError, ValueError, IndexError, OverflowError):
@@ -151,10 +164,15 @@ def _parse_retry_after(retry_after: Optional[str]) -> Optional[float]:
     def _calculate_retry_delay(
         attempt: int, retry_after: Optional[str] = None
     ) -> float:
-        """Calculate retry delay with exponential backoff and jitter."""
+        """Calculate retry delay with exponential backoff and jitter.
+
+        A valid Retry-After header wins over backoff but is capped at
+        ``MAX_RETRY_AFTER`` so a huge value cannot overflow ``time.sleep`` or
+        leave an async retry waiting indefinitely.
+        """
         parsed_retry_after = _BaseWorkOSClient._parse_retry_after(retry_after)
         if parsed_retry_after is not None:
-            return parsed_retry_after
+            return min(parsed_retry_after, float(MAX_RETRY_AFTER))
         delay = min(INITIAL_RETRY_DELAY * (RETRY_MULTIPLIER**attempt), MAX_RETRY_DELAY)
         return delay * (0.5 + random.random())
 
diff --git a/tests/test_generated_client.py b/tests/test_generated_client.py
index 3dcdd66f..09cd20d6 100644
--- a/tests/test_generated_client.py
+++ b/tests/test_generated_client.py
@@ -2,6 +2,9 @@
 
 """Client tests: retries, errors, context manager, idempotency."""
 
+from datetime import datetime, timedelta, timezone
+from email.utils import format_datetime
+
 import httpx2 as httpx
 import pytest
 
@@ -30,6 +33,27 @@
     ServerError,
 )
 
+# Retry-After values that must never reach time.sleep/asyncio.sleep unbounded,
+# paired with the sleep range the client must use instead: non-finite or
+# non-integer forms fall back to the first backoff step (INITIAL_RETRY_DELAY
+# with +/-50% jitter), huge finite values and far-future dates are capped at
+# MAX_RETRY_AFTER.
+_BACKOFF_FIRST_STEP = (
+    generated_client_module.INITIAL_RETRY_DELAY * 0.5,
+    generated_client_module.INITIAL_RETRY_DELAY * 1.5,
+)
+_CAPPED = (
+    float(generated_client_module.MAX_RETRY_AFTER),
+    float(generated_client_module.MAX_RETRY_AFTER),
+)
+UNSAFE_RETRY_AFTER_CASES = [
+    ("NaN", _BACKOFF_FIRST_STEP),
+    ("Infinity", _BACKOFF_FIRST_STEP),
+    ("1e309", _BACKOFF_FIRST_STEP),
+    ("99999999999", _CAPPED),
+    ("Fri, 31 Dec 9999 23:59:59 GMT", _CAPPED),
+]
+
 
 class TestWorkOSClient:
     def test_missing_credentials_raise(self):
@@ -381,6 +405,54 @@ def test_empty_body_sends_json(self, httpx_mock):
     def test_calculate_retry_delay_uses_retry_after_seconds(self):
         assert WorkOSClient._calculate_retry_delay(1, "30") == 30.0
 
+    @pytest.mark.parametrize(
+        "retry_after", ["3600", "99999999999", "Fri, 31 Dec 9999 23:59:59 GMT"]
+    )
+    def test_calculate_retry_delay_caps_retry_after(self, retry_after):
+        assert WorkOSClient._calculate_retry_delay(0, retry_after) == float(
+            generated_client_module.MAX_RETRY_AFTER
+        )
+
+    @pytest.mark.parametrize(
+        "retry_after",
+        ["NaN", "Infinity", "1e309", "-1", "1.5", "0x10", "1" * 400, "not a date"],
+    )
+    def test_parse_retry_after_rejects_non_delay_seconds(self, retry_after):
+        assert WorkOSClient._parse_retry_after(retry_after) is None
+
+    def test_parse_retry_after_keeps_raw_server_value(self):
+        assert WorkOSClient._parse_retry_after("3600") == 3600.0
+
+    def test_parse_retry_after_http_date(self):
+        retry_at = datetime.now(timezone.utc) + timedelta(seconds=30)
+        parsed = WorkOSClient._parse_retry_after(format_datetime(retry_at, usegmt=True))
+        assert parsed is not None
+        assert 28.0 <= parsed <= 30.0
+
+    def test_parse_retry_after_past_http_date_is_zero(self):
+        assert WorkOSClient._parse_retry_after("Thu, 01 Jan 1970 00:00:00 GMT") == 0.0
+
+    @pytest.mark.parametrize(
+        ("retry_after", "expected_range"), UNSAFE_RETRY_AFTER_CASES
+    )
+    def test_retry_sleep_is_finite_and_bounded(
+        self, httpx_mock, monkeypatch, retry_after, expected_range
+    ):
+        delays: list[float] = []
+        monkeypatch.setattr(generated_client_module.time, "sleep", delays.append)
+        httpx_mock.add_response(
+            status_code=503,
+            headers={"Retry-After": retry_after},
+            json={"message": "down"},
+        )
+        httpx_mock.add_response(json={"ok": True})
+        client = WorkOSClient(api_key="sk_test_123", client_id="client_test")
+        assert client.request("GET", ("test",)) == {"ok": True}
+        client.close()
+        assert len(delays) == 1
+        low, high = expected_range
+        assert low <= delays[0] <= high
+
     def test_retry_exhaustion_raises_rate_limit(self, httpx_mock, monkeypatch):
         monkeypatch.setattr(generated_client_module.time, "sleep", lambda _: None)
         for _ in range(4):
@@ -410,6 +482,37 @@ def test_rate_limit_retry_after_is_parsed(self, httpx_mock):
         assert exc_info.value.retry_after == 30.0
         client.close()
 
+    def test_rate_limit_retry_after_is_not_capped_on_error(self, httpx_mock):
+        httpx_mock.add_response(
+            status_code=429,
+            headers={"Retry-After": "3600"},
+            json={"message": "Slow down"},
+        )
+        client = WorkOSClient(
+            api_key="sk_test_123", client_id="client_test", max_retries=0
+        )
+        with pytest.raises(RateLimitExceededError) as exc_info:
+            client.request("GET", ("test",))
+        assert exc_info.value.retry_after == 3600.0
+        client.close()
+
+    @pytest.mark.parametrize("retry_after", ["NaN", "Infinity", "1e309"])
+    def test_rate_limit_retry_after_is_none_for_invalid_header(
+        self, httpx_mock, retry_after
+    ):
+        httpx_mock.add_response(
+            status_code=429,
+            headers={"Retry-After": retry_after},
+            json={"message": "Slow down"},
+        )
+        client = WorkOSClient(
+            api_key="sk_test_123", client_id="client_test", max_retries=0
+        )
+        with pytest.raises(RateLimitExceededError) as exc_info:
+            client.request("GET", ("test",))
+        assert exc_info.value.retry_after is None
+        client.close()
+
     def test_timeout_error_is_wrapped(self, httpx_mock, monkeypatch):
         monkeypatch.setattr(generated_client_module.time, "sleep", lambda _: None)
         httpx_mock.add_exception(httpx.TimeoutException("timed out"))
@@ -705,6 +808,31 @@ async def test_raises_429(self, httpx_mock):
             await client.request("GET", ("test",))
         await client.close()
 
+    @pytest.mark.parametrize(
+        ("retry_after", "expected_range"), UNSAFE_RETRY_AFTER_CASES
+    )
+    async def test_retry_sleep_is_finite_and_bounded(
+        self, httpx_mock, monkeypatch, retry_after, expected_range
+    ):
+        delays: list[float] = []
+
+        async def _sleep(delay: float) -> None:
+            delays.append(delay)
+
+        monkeypatch.setattr(generated_client_module.asyncio, "sleep", _sleep)
+        httpx_mock.add_response(
+            status_code=503,
+            headers={"Retry-After": retry_after},
+            json={"message": "down"},
+        )
+        httpx_mock.add_response(json={"ok": True})
+        client = AsyncWorkOSClient(api_key="sk_test_123", client_id="client_test")
+        assert await client.request("GET", ("test",)) == {"ok": True}
+        await client.close()
+        assert len(delays) == 1
+        low, high = expected_range
+        assert low <= delays[0] <= high
+
     async def test_raises_500(self, httpx_mock):
         httpx_mock.add_response(
             status_code=500,