diff --git a/parso/python/grammar310.txt b/parso/python/grammar310.txt
index 159da4e..3c39bb5 100644
--- a/parso/python/grammar310.txt
+++ b/parso/python/grammar310.txt
@@ -52,7 +52,7 @@ small_stmt: (expr_stmt | del_stmt | pass_stmt | flow_stmt |
              import_stmt | global_stmt | nonlocal_stmt | assert_stmt)
 expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist) |
                      ('=' (yield_expr|testlist_star_expr))*)
-annassign: ':' test ['=' test]
+annassign: ':' test ['=' (yield_expr|testlist_star_expr)]
 testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [',']
 augassign: ('+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' | '^=' |
             '<<=' | '>>=' | '**=' | '//=')
diff --git a/parso/python/grammar38.txt b/parso/python/grammar38.txt
index 40908ed..3e94309 100644
--- a/parso/python/grammar38.txt
+++ b/parso/python/grammar38.txt
@@ -52,7 +52,7 @@ small_stmt: (expr_stmt | del_stmt | pass_stmt | flow_stmt |
              import_stmt | global_stmt | nonlocal_stmt | assert_stmt)
 expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist) |
                      ('=' (yield_expr|testlist_star_expr))*)
-annassign: ':' test ['=' test]
+annassign: ':' test ['=' (yield_expr|testlist_star_expr)]
 testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [',']
 augassign: ('+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' | '^=' |
             '<<=' | '>>=' | '**=' | '//=')
diff --git a/parso/python/grammar39.txt b/parso/python/grammar39.txt
index 159da4e..3c39bb5 100644
--- a/parso/python/grammar39.txt
+++ b/parso/python/grammar39.txt
@@ -52,7 +52,7 @@ small_stmt: (expr_stmt | del_stmt | pass_stmt | flow_stmt |
              import_stmt | global_stmt | nonlocal_stmt | assert_stmt)
 expr_stmt: testlist_star_expr (annassign | augassign (yield_expr|testlist) |
                      ('=' (yield_expr|testlist_star_expr))*)
-annassign: ':' test ['=' test]
+annassign: ':' test ['=' (yield_expr|testlist_star_expr)]
 testlist_star_expr: (test|star_expr) (',' (test|star_expr))* [',']
 augassign: ('+=' | '-=' | '*=' | '@=' | '/=' | '%=' | '&=' | '|=' | '^=' |
             '<<=' | '>>=' | '**=' | '//=')
diff --git a/test/test_parser.py b/test/test_parser.py
index dff126a..e9a9dda 100644
--- a/test/test_parser.py
+++ b/test/test_parser.py
@@ -194,6 +194,9 @@ def test_no_error_nodes(each_version):
 def test_named_expression(works_ge_py38):
     works_ge_py38.parse("(a := 1, a + 1)")
 
+def test_extended_rhs_annassign(works_ge_py38):
+    works_ge_py38.parse("x: y = z,")
+    works_ge_py38.parse("x: Tuple[int, ...] = z, *q, w")
 
 @pytest.mark.parametrize(
     'param_code', [