diff --git a/Doc/c-api/arg.rst b/Doc/c-api/arg.rst
index d4dda7c..a171ac7 100644
--- a/Doc/c-api/arg.rst
+++ b/Doc/c-api/arg.rst
@@ -260,9 +260,11 @@ Numbers
 ``n`` (:class:`int`) [Py_ssize_t]
    Convert a Python integer to a C :c:type:`Py_ssize_t`.
 
-``c`` (:class:`bytes` of length 1) [char]
-   Convert a Python byte, represented as a :class:`bytes` object of length 1,
-   to a C :c:type:`char`.
+``c`` (:class:`bytes` or :class:`bytearray` of length 1) [char]
+   Convert a Python byte, represented as a :class:`bytes` or
+   :class:`bytearray` object of length 1, to a C :c:type:`char`.
+
+   .. versionchanged:: 3.3 Allow :class:`bytearray` objects
 
 ``C`` (:class:`str` of length 1) [int]
    Convert a Python character, represented as a :class:`str` object of
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index 234b56c..d32a44b 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -475,6 +475,27 @@ class BaseBytesTest(unittest.TestCase):
         self.assertRaises(TypeError, self.type2test(b'abc').lstrip, 'b')
         self.assertRaises(TypeError, self.type2test(b'abc').rstrip, 'b')
 
+    def test_center(self):
+        # Fill character can be either bytes or bytearray (issue 12380)
+        b = self.type2test(b'abc')
+        for fill_type in (bytes, bytearray):
+            self.assertEqual(b.center(7, fill_type(b'-')),
+                             self.type2test(b'--abc--'))
+
+    def test_ljust(self):
+        # Fill character can be either bytes or bytearray (issue 12380)
+        b = self.type2test(b'abc')
+        for fill_type in (bytes, bytearray):
+            self.assertEqual(b.ljust(7, fill_type(b'-')),
+                             self.type2test(b'abc----'))
+
+    def test_rjust(self):
+        # Fill character can be either bytes or bytearray (issue 12380)
+        b = self.type2test(b'abc')
+        for fill_type in (bytes, bytearray):
+            self.assertEqual(b.rjust(7, fill_type(b'-')),
+                             self.type2test(b'----abc'))
+
     def test_ord(self):
         b = self.type2test(b'\0A\x7f\x80\xff')
         self.assertEqual([ord(b[i:i+1]) for i in range(len(b))],
diff --git a/Lib/test/test_getargs2.py b/Lib/test/test_getargs2.py
index 3d9c06a..768ea8d 100644
--- a/Lib/test/test_getargs2.py
+++ b/Lib/test/test_getargs2.py
@@ -294,6 +294,15 @@ class Keywords_TestCase(unittest.TestCase):
             self.fail('TypeError should have been raised')
 
 class Bytes_TestCase(unittest.TestCase):
+    def test_c(self):
+        from _testcapi import getargs_c
+        self.assertRaises(TypeError, getargs_c, b'abc')  # len > 1
+        self.assertEqual(getargs_c(b'a'), b'a')
+        self.assertEqual(getargs_c(bytearray(b'a')), b'a')
+        self.assertRaises(TypeError, getargs_c, memoryview(b'a'))
+        self.assertRaises(TypeError, getargs_c, 's')
+        self.assertRaises(TypeError, getargs_c, None)
+
     def test_s(self):
         from _testcapi import getargs_s
         self.assertEqual(getargs_s('abc\xe9'), b'abc\xc3\xa9')
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index 35d25e6..51c79c9 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -1003,6 +1003,15 @@ test_k_code(PyObject *self)
 }
 
 static PyObject *
+getargs_c(PyObject *self, PyObject *args)
+{
+    char c;
+    if (!PyArg_ParseTuple(args, "c", &c))
+        return NULL;
+    return PyBytes_FromStringAndSize(&c, 1);
+}
+
+static PyObject *
 getargs_s(PyObject *self, PyObject *args)
 {
     char *str;
@@ -2289,6 +2298,7 @@ static PyMethodDef TestMethods[] = {
         (PyCFunction)test_long_long_and_overflow, METH_NOARGS},
     {"test_L_code",             (PyCFunction)test_L_code,        METH_NOARGS},
 #endif
+    {"getargs_c",               getargs_c,                       METH_VARARGS},
     {"getargs_s",               getargs_s,                       METH_VARARGS},
     {"getargs_s_star",          getargs_s_star,                  METH_VARARGS},
     {"getargs_s_hash",          getargs_s_hash,                  METH_VARARGS},
diff --git a/Python/getargs.c b/Python/getargs.c
index 4b57153..c3da368 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -828,6 +828,8 @@ convertsimple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
         char *p = va_arg(*p_va, char *);
         if (PyBytes_Check(arg) && PyBytes_Size(arg) == 1)
             *p = PyBytes_AS_STRING(arg)[0];
+        else if (PyByteArray_Check(arg) && PyByteArray_Size(arg) == 1)
+            *p = PyByteArray_AS_STRING(arg)[0];
         else
             return converterr("a byte string of length 1", arg, msgbuf, bufsize);
         break;