diff --git a/library/std/src/fs.rs b/library/std/src/fs.rs
index 801baf3d99072..0e306d23dd936 100644
--- a/library/std/src/fs.rs
+++ b/library/std/src/fs.rs
@@ -2874,6 +2874,8 @@ pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
 ///
 /// Consider ignoring the error if validating the removal is not required for your use case.
 ///
+/// This function may return [`io::ErrorKind::DirectoryNotEmpty`] if the directory is concurrently
+/// written into, which typically indicates some contents were removed but not all.
 /// [`io::ErrorKind::NotFound`] is only returned if no removal occurs.
 ///
 /// [`fs::remove_file`]: remove_file