diff --git a/pyproject.toml b/pyproject.toml
index 2c176e0..0f29e9e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -38,7 +38,6 @@ dev = [
 test = [
     "coverage",
     "nbmake",
-    "six",
 ]
 all = ["anonipy[dev,test]"]