diff --git a/Lib/_pydecimal.py b/Lib/_pydecimal.py
index 359690003fe1605..6c0177d08bf8466 100644
--- a/Lib/_pydecimal.py
+++ b/Lib/_pydecimal.py
@@ -6152,7 +6152,7 @@ def _convert_for_comparison(self, other, equality_op=False):
 (?P<alt>\#)?
 (?P<zeropad>0)?
 (?P<minimumwidth>(?!0)\d+)?
-(?P<thousands_sep>,)?
+(?P<thousands_sep>[,'])?
 (?:\.(?P<precision>0|(?!0)\d+))?
 (?P<type>[eEfFgGn%])?
 \Z
@@ -6241,10 +6241,16 @@ def _parse_format_specifier(format_spec, _localeconv=None):
         format_dict['grouping'] = _localeconv['grouping']
         format_dict['decimal_point'] = _localeconv['decimal_point']
     else:
-        if format_dict['thousands_sep'] is None:
-            format_dict['thousands_sep'] = ''
         format_dict['grouping'] = [3, 0]
         format_dict['decimal_point'] = '.'
+        if format_dict['thousands_sep'] is None:
+            format_dict['thousands_sep'] = ''
+        elif format_dict['thousands_sep'] == "'":
+            if _localeconv is None:
+                _localeconv = _locale.localeconv()
+            format_dict['thousands_sep'] = _localeconv['thousands_sep']
+            format_dict['grouping'] = _localeconv['grouping']
+            format_dict['decimal_point'] = _localeconv['decimal_point']
 
     return format_dict
 
diff --git a/Lib/test/test_decimal.py b/Lib/test/test_decimal.py
index 58bde54b0a88a16..1977ae7dd33813d 100644
--- a/Lib/test/test_decimal.py
+++ b/Lib/test/test_decimal.py
@@ -1075,7 +1075,7 @@ def test_formatting(self):
         # bytes format argument
         self.assertRaises(TypeError, Decimal(1).__format__, b'-020')
 
-    def test_n_format(self):
+    def test_locale_format(self):
         Decimal = self.decimal.Decimal
 
         try:
@@ -1164,6 +1164,40 @@ def get_fmt(x, override=None, fmt='n'):
         self.assertEqual(get_fmt(Decimal('-1.5'), dotsep_wide, '020n'),
                          '-0\u00b4000\u00b4000\u00b4000\u00b4001\u00bf5')
 
+        # locale grouping modifier
+        self.assertEqual(get_fmt(123456789, en_US, "'f"), '123,456,789')
+        self.assertEqual(get_fmt(123456789, fr_FR, "'f"), '123456789')
+        self.assertEqual(get_fmt(123456789, ru_RU, "'f"), '123 456 789')
+        self.assertEqual(get_fmt(1234567890123, crazy, "'f"),
+                         '123456-78-9012-3')
+
+        self.assertEqual(get_fmt('123456789.123', en_US, "'.2f"),
+                         '123,456,789.12')
+        self.assertEqual(get_fmt('123456789.123', fr_FR, "'.2f"),
+                         '123456789,12')
+        self.assertEqual(get_fmt('123456789.123', ru_RU, "'.2f"),
+                         '123 456 789,12')
+        self.assertEqual(get_fmt('1234567890123.123', crazy, "'.2f"),
+                         '123456-78-9012-3&12')
+
+        self.assertEqual(get_fmt(123456789, en_US, "'.6e"), '1.234568e+8')
+        self.assertEqual(get_fmt(123456789, fr_FR, "'.6e"), '1,234568e+8')
+        self.assertEqual(get_fmt(123456789, ru_RU, "'.6e"), '1,234568e+8')
+        self.assertEqual(get_fmt(123456789, crazy, "'.6e"), '1&234568e+8')
+
+        self.assertEqual(get_fmt(123456789, en_US, "'.6g"), '1.23457e+8')
+        self.assertEqual(get_fmt(123456789, fr_FR, "'.6g"), '1,23457e+8')
+        self.assertEqual(get_fmt(123456789, ru_RU, "'.6g"), '1,23457e+8')
+        self.assertEqual(get_fmt(123456789, crazy, "'.6g"), '1&23457e+8')
+
+        self.assertEqual(get_fmt(12345, en_US, "05'g"), '12,345')
+        self.assertEqual(get_fmt(12345, en_US, "06'g"), '12,345')
+        self.assertEqual(get_fmt(12345, en_US, "07'g"), '012,345')
+        self.assertEqual(get_fmt(12345, en_US, "08'g"), '0,012,345')
+        self.assertEqual(get_fmt(12345, en_US, "09'g"), '0,012,345')
+        self.assertEqual(get_fmt(12345, en_US, "010'g"), '00,012,345')
+
+
     @run_with_locale('LC_ALL', 'ps_AF')
     def test_wide_char_separator_decimal_point(self):
         # locale with wide char separator and decimal point
diff --git a/Modules/_decimal/libmpdec/io.c b/Modules/_decimal/libmpdec/io.c
index f45e558f1a95734..e86bc8ef5526236 100644
--- a/Modules/_decimal/libmpdec/io.c
+++ b/Modules/_decimal/libmpdec/io.c
@@ -846,6 +846,15 @@ mpd_parse_fmt_str(mpd_spec_t *spec, const char *fmt, int caps)
         cp++;
     }
 
+    /* locale specific thousands separator */
+    if (*cp == '\'') {
+        struct lconv *lc = localeconv();
+        spec->dot = lc->decimal_point;
+        spec->sep = lc->thousands_sep;
+        spec->grouping = lc->grouping;
+        cp++;
+    }
+
     /* fraction digits or significant digits */
     if (*cp == '.') {
         cp++;