diff --git a/setuptools_scm/git.py b/setuptools_scm/git.py
index 10280e50..2b4e19de 100644
--- a/setuptools_scm/git.py
+++ b/setuptools_scm/git.py
@@ -30,7 +30,7 @@ def from_potential_worktree(cls, wd):
         return cls(real_wd)
 
     def is_dirty(self):
-        out, _, _ = self.do_ex("git status --porcelain")
+        out, _, _ = self.do_ex("git status --porcelain --untracked-files=no")
         return bool(out)
 
     def node(self):