diff --git a/pkgs/development/python-modules/readability-lxml/default.nix b/pkgs/development/python-modules/readability-lxml/default.nix
index e016767db614..30453064016a 100644
--- a/pkgs/development/python-modules/readability-lxml/default.nix
+++ b/pkgs/development/python-modules/readability-lxml/default.nix
@@ -25,7 +25,10 @@ buildPythonPackage rec {
 
   build-system = [ poetry-core ];
 
-  pythonRelaxDeps = [ "lxml" ];
+  pythonRelaxDeps = [
+    "chardet"
+    "lxml"
+  ];
 
   dependencies = [
     chardet