diff --git a/library/std/src/sys/unix/os.rs b/library/std/src/sys/unix/os.rs
index 3c3770708b1..7c70ddbd9b9 100644
--- a/library/std/src/sys/unix/os.rs
+++ b/library/std/src/sys/unix/os.rs
@@ -125,7 +125,9 @@ pub fn error_string(errno: i32) -> String {
         }
 
         let p = p as *const _;
-        str::from_utf8(CStr::from_ptr(p).to_bytes()).unwrap().to_owned()
+        // We can't always expect a UTF-8 environment. When we don't get that luxury,
+        // it's better to give a low-quality error message than none at all.
+        String::from_utf8_lossy(CStr::from_ptr(p).to_bytes()).into()
     }
 }