diff --git a/grayskull/pypi/pypi.py b/grayskull/pypi/pypi.py
index 1aa770fe8..9ea42e3ce 100644
--- a/grayskull/pypi/pypi.py
+++ b/grayskull/pypi/pypi.py
@@ -218,10 +218,13 @@ def __fake_distutils_setup(*args, **kwargs):
 
             def _fix_list_requirements(key_deps: str) -> List:
                 """Fix when dependencies have lists inside of another sequence"""
-                if not kwargs.get(key_deps):
-                    return kwargs.get(key_deps)
+                val_deps = kwargs.get(key_deps)
+                if not val_deps:
+                    return val_deps
                 list_req = []
-                for val in kwargs.get(key_deps):
+                if isinstance(val_deps, str):
+                    val_deps = [val_deps]
+                for val in val_deps:
                     if isinstance(val, (tuple, list)):
                         list_req.extend(list(map(str, val)))
                     else:
diff --git a/tests/test_pypi.py b/tests/test_pypi.py
index 546d71492..ed5036f65 100644
--- a/tests/test_pypi.py
+++ b/tests/test_pypi.py
@@ -226,6 +226,16 @@ def test_injection_distutils_compiler_gsw():
     assert data["packages"] == ["gsw"]
 
 
+def test_injection_distutils_setup_reqs_ensure_list():
+    pkg_name, pkg_ver = "pyinstaller-hooks-contrib", "2020.7"
+    recipe = PyPi(name=pkg_name, version=pkg_ver)
+    data = recipe._get_sdist_metadata(
+        f"https://pypi.io/packages/source/p/{pkg_name}/{pkg_name}-{pkg_ver}.tar.gz",
+        pkg_name,
+    )
+    assert data.get("setup_requires") == ["setuptools >= 30.3.0"]
+
+
 def test_merge_pypi_sdist_metadata():
     recipe = PyPi(name="gsw", version="3.3.1")
     pypi_metadata = recipe._get_pypi_metadata(name="gsw", version="3.3.1")