diff --git a/pyproject.toml b/pyproject.toml
index 01f775d..759eb4f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,7 +25,6 @@ classifiers = [
 requires-python = ">=3.10, <4.0"
 dependencies = [
     "python-baseconv>=1.2.0,<2.0",
-    "six>=1.10.0,<2.0",
     "morphys>=1.0,<2.0",
 ]