diff --git a/benedict/core/keypaths.py b/benedict/core/keypaths.py
index ca4c9dea..9ba6151f 100644
--- a/benedict/core/keypaths.py
+++ b/benedict/core/keypaths.py
@@ -13,9 +13,11 @@ def keypaths(
     indexes: bool = False,
     sort: bool = True,
 ) -> list[str]:
-    separator = separator or "."
+    separator = "." if separator is None else separator
     if not type_util.is_string(separator):
         raise ValueError("separator argument must be a (non-empty) string.")
+    if not separator:
+        raise ValueError("separator argument must be a (non-empty) string.")
     kls = keylists(d, indexes=indexes)
     kps = [separator.join([f"{key}" for key in kl]) for kl in kls]
     if sort:
diff --git a/tests/core/test_keypaths.py b/tests/core/test_keypaths.py
index 5d4faa6f..62834ad1 100644
--- a/tests/core/test_keypaths.py
+++ b/tests/core/test_keypaths.py
@@ -106,6 +106,10 @@ def test_keypaths_with_invalid_separator(self) -> None:
         with self.assertRaises(ValueError):
             _ = _keypaths(i, separator=True)  # type: ignore[arg-type]
 
+    def test_keypaths_with_empty_separator(self) -> None:
+        with self.assertRaises(ValueError):
+            _ = _keypaths({"a": {"b": 1}}, separator="")
+
     def test_keypaths_without_separator(self) -> None:
         i = {
             "a": 1,