diff --git a/graphene/types/datetime.py b/graphene/types/datetime.py
index 7bfd9bd2..d8388f8d 100644
--- a/graphene/types/datetime.py
+++ b/graphene/types/datetime.py
@@ -1,5 +1,7 @@
 import datetime
 
+from dateutil.parser import isoparse
+
 from graphql.error import GraphQLError
 from graphql.language import StringValueNode, print_ast
 
@@ -71,7 +73,7 @@ class DateTime(Scalar):
                 f"DateTime cannot represent non-string value: {repr(value)}"
             )
         try:
-            return datetime.datetime.fromisoformat(value)
+            return isoparse(value)
         except ValueError:
             raise GraphQLError(f"DateTime cannot represent value: {repr(value)}")
 
diff --git a/graphene/types/tests/test_datetime.py b/graphene/types/tests/test_datetime.py
index 12927617..5d4cb604 100644
--- a/graphene/types/tests/test_datetime.py
+++ b/graphene/types/tests/test_datetime.py
@@ -226,6 +226,23 @@ def test_time_query_variable(sample_time):
     assert not result.errors
     assert result.data == {"time": isoformat}
 
+def test_support_isoformat():
+    isoformat = 20111104
+
+    # test time variable provided as Python time
+    result = schema.execute(
+        """query Test($time: Time){ time(at: $time) }""",
+        variables={"time": sample_time},
+    )
+    assert not result.errors
+    assert result.data == {"time": isoformat}
+
+    # test time variable in string representation
+    result = schema.execute(
+        """query Test($time: Time){ time(at: $time) }""", variables={"time": isoformat}
+    )
+    assert not result.errors
+    assert result.data == {"time": isoformat}
 
 def test_bad_variables(sample_date, sample_datetime, sample_time):
     def _test_bad_variables(type_, input_):
diff --git a/setup.py b/setup.py
index 33ceba50..b8db0e0c 100644
--- a/setup.py
+++ b/setup.py
@@ -84,6 +84,7 @@ setup(
         "graphql-core>=3.1,<3.3",
         "graphql-relay>=3.1,<3.3",
         "typing-extensions>=4.7.1,<5",
+        "python-dateutil>=2.7.0,<3"
     ],
     tests_require=tests_require,
     extras_require={"test": tests_require, "dev": dev_requires},