diff --git a/src/marshmallow/schema.py b/src/marshmallow/schema.py
index cde8c080f..4e7fd828f 100644
--- a/src/marshmallow/schema.py
+++ b/src/marshmallow/schema.py
@@ -374,7 +374,7 @@ def __init__(
         context: dict | None = None,
         load_only: types.StrSequenceOrSet = (),
         dump_only: types.StrSequenceOrSet = (),
-        partial: bool | types.StrSequenceOrSet = False,
+        partial: bool | types.StrSequenceOrSet | None = None,
         unknown: str | None = None,
     ):
         # Raise error if only or exclude is passed as string, not list of strings
@@ -590,7 +590,7 @@ def _deserialize(
         *,
         error_store: ErrorStore,
         many: bool = False,
-        partial=False,
+        partial=None,
         unknown=RAISE,
         index=None,
     ) -> _T | list[_T]:
@@ -657,7 +657,7 @@ def _deserialize(
                         f[len_prefix:] for f in partial if f.startswith(prefix)
                     ]
                     d_kwargs["partial"] = sub_partial
-                else:
+                elif partial is not None:
                     d_kwargs["partial"] = partial
 
                 def getter(
@@ -1089,7 +1089,7 @@ def _invoke_load_processors(
         *,
         many: bool,
         original_data,
-        partial: bool | types.StrSequenceOrSet,
+        partial: bool | types.StrSequenceOrSet | None,
     ):
         # This has to invert the order of the dump processors, so run the pass_many
         # processors first.
@@ -1166,7 +1166,7 @@ def _invoke_schema_validators(
         data,
         original_data,
         many: bool,
-        partial: bool | types.StrSequenceOrSet,
+        partial: bool | types.StrSequenceOrSet | None,
         field_errors: bool = False,
     ):
         for attr_name in self._hooks[(VALIDATES_SCHEMA, pass_many)]:
diff --git a/tests/test_deserialization.py b/tests/test_deserialization.py
index 6a2c7a87b..29cab67b7 100644
--- a/tests/test_deserialization.py
+++ b/tests/test_deserialization.py
@@ -2236,6 +2236,21 @@ class SchemaB(Schema):
         with pytest.raises(ValidationError):
             SchemaB().load(b_dict, partial=("z.y",))
 
+    def test_nested_partial_default(self):
+        class SchemaA(Schema):
+            x = fields.Integer(required=True)
+            y = fields.Integer(required=True)
+
+        class SchemaB(Schema):
+            z = fields.Nested(SchemaA(partial=("x",)))
+
+        b_dict = {"z": {"y": 42}}
+        # Nested partial args should be respected.
+        result = SchemaB().load(b_dict)
+        assert result["z"]["y"] == 42
+        with pytest.raises(ValidationError):
+            SchemaB().load({"z": {"x": 0}})
+
 
 @pytest.mark.parametrize("FieldClass", ALL_FIELDS)
 def test_required_field_failure(FieldClass):  # noqa