diff --git a/setup.py b/setup.py
index 2e10c4f..707217f 100644
--- a/setup.py
+++ b/setup.py
@@ -66,6 +66,8 @@
             "requests",
             "aiohttp",
             "httpx",
+            # https://github.com/encode/httpx/discussions/3214#discussioncomment-10830925
+            "httpcore<1.0.6",
             "respx",
             "opentelemetry-api",
             "opentelemetry-sdk",