diff --git a/homeassistant/package_constraints.txt b/homeassistant/package_constraints.txt
index 30927b9cd32..630eb789d00 100644
--- a/homeassistant/package_constraints.txt
+++ b/homeassistant/package_constraints.txt
@@ -40,6 +40,10 @@ urllib3>=1.24.3
 # Constrain H11 to ensure we get a new enough version to support non-rfc line endings
 h11>=0.12.0
 
+# Constrain httpcore to fix exception when connection dropped
+# https://github.com/encode/httpcore/issues/239
+httpcore>=0.12.3
+
 # Constrain httplib2 to protect against CVE-2020-11078
 httplib2>=0.18.0
 
diff --git a/script/gen_requirements_all.py b/script/gen_requirements_all.py
index 130fd2cc245..dc1ef9a471b 100755
--- a/script/gen_requirements_all.py
+++ b/script/gen_requirements_all.py
@@ -68,6 +68,10 @@ urllib3>=1.24.3
 # Constrain H11 to ensure we get a new enough version to support non-rfc line endings
 h11>=0.12.0
 
+# Constrain httpcore to fix exception when connection dropped
+# https://github.com/encode/httpcore/issues/239
+httpcore>=0.12.3
+
 # Constrain httplib2 to protect against CVE-2020-11078
 httplib2>=0.18.0