diff --git a/library/std/src/ffi/os_str.rs b/library/std/src/ffi/os_str.rs
index 247bdd954589c..f171f142b4237 100644
--- a/library/std/src/ffi/os_str.rs
+++ b/library/std/src/ffi/os_str.rs
@@ -615,6 +615,14 @@ impl Hash for OsString {
     }
 }
 
+#[stable(feature = "os_string_fmt_write", since = "1.64.0")]
+impl fmt::Write for OsString {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.push(s);
+        Ok(())
+    }
+}
+
 impl OsStr {
     /// Coerces into an `OsStr` slice.
     ///