diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index c02fb52..359dc96 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -1125,7 +1125,7 @@
                            restore_signals, start_new_session):
             """Execute program (POSIX version)"""
 
-            if isinstance(args, str):
+            if isinstance(args, (str, bytes)):
                 args = [args]
             else:
                 args = list(args)
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 9e267eb..d91a4a6 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1059,6 +1059,11 @@
         exitcode = subprocess.call([abs_program, "-c", "pass"])
         self.assertEqual(exitcode, 0)
 
+        # absolute bytes path as a string
+        cmd = b"'" + abs_program + b"' -c pass"
+        exitcode = subprocess.call(cmd, shell=True)
+        self.assertEqual(exitcode, 0)
+
         # bytes program, unicode PATH
         env = os.environ.copy()
         env["PATH"] = path