diff --git a/py-polars/polars/config.py b/py-polars/polars/config.py
index fd31a1e425d6..3077cfde8fc6 100644
--- a/py-polars/polars/config.py
+++ b/py-polars/polars/config.py
@@ -1353,6 +1353,9 @@ def set_tbl_width_chars(cls, width: int | None) -> type[Config]:
         """
         if width is None:
             os.environ.pop("POLARS_TABLE_WIDTH", None)
+        elif width < 0:
+            msg = "width should be positive"
+            raise ValueError(msg)
         else:
             os.environ["POLARS_TABLE_WIDTH"] = str(width)
         return cls
diff --git a/py-polars/tests/unit/test_config.py b/py-polars/tests/unit/test_config.py
index 9535f11b3825..2d8b29ed6c74 100644
--- a/py-polars/tests/unit/test_config.py
+++ b/py-polars/tests/unit/test_config.py
@@ -371,6 +371,9 @@ def test_set_tbl_width_chars() -> None:
     with pl.Config(tbl_width_chars=87):
         assert max(len(line) for line in str(df).split("\n")) == 87
 
+    with pytest.raises(ValueError, match="width should be positive"):
+        pl.Config.set_tbl_width_chars(-1)
+
 
 def test_shape_below_table_and_inlined_dtype() -> None:
     df = pl.DataFrame({"a": [1, 2], "b": [3, 4], "c": [5, 6]})