diff --git a/Misc/NEWS b/Misc/NEWS
index 34329933463..81d3e81c543 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -93,6 +93,10 @@ C-API
 Library
 -------
 
+- Issue #9603: posix.ttyname() and posix.ctermid() decode the terminal name
+  using the filesystem encoding and surrogateescape error handler. Patch
+  written by David Watson.
+
 - Issue #8688: MANIFEST files created by distutils now include a magic
   comment indicating they are generated.  Manually maintained MANIFESTs
   without this marker will not be overwritten or removed.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 951323bc91a..6d92544982c 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -1769,7 +1769,7 @@ posix_ttyname(PyObject *self, PyObject *args)
 #endif
     if (ret == NULL)
         return posix_error();
-    return PyUnicode_FromString(ret);
+    return PyUnicode_DecodeFSDefault(ret);
 }
 #endif
 
@@ -1791,7 +1791,7 @@ posix_ctermid(PyObject *self, PyObject *noargs)
 #endif
     if (ret == NULL)
         return posix_error();
-    return PyUnicode_FromString(buffer);
+    return PyUnicode_DecodeFSDefault(buffer);
 }
 #endif