diff --git a/doc/en/changelog.rst b/doc/en/changelog.rst
index 5dfba97ce..383479e07 100644
--- a/doc/en/changelog.rst
+++ b/doc/en/changelog.rst
@@ -34,6 +34,7 @@ pytest 6.2.5 (2021-08-29)
 Bug Fixes
 ---------
 
+- `#9175 <https://github.com/pytest-dev/pytest/issues/9175>`_: Fix duplicate parametrizes in the same module.
 - `#7792 <https://github.com/pytest-dev/pytest/issues/7792>`_: Fix missing marks when inheritance from multiple classes.
 
 
diff --git a/src/_pytest/mark/structures.py b/src/_pytest/mark/structures.py
index 053297fa2..1abda3596 100644
--- a/src/_pytest/mark/structures.py
+++ b/src/_pytest/mark/structures.py
@@ -24,6 +24,7 @@ import attr
 
 from .._code import getfslineno
 from ..compat import ascii_escaped
+from ..compat import cached_property
 from ..compat import final
 from ..compat import NOTSET
 from ..compat import NotSetType
@@ -259,6 +260,11 @@ class Mark:
             _ispytest=True,
         )
 
+    @cached_property
+    def unique_name(self):
+        # For "parametrize" mark, the name value is "parametrize" and not the name that the user was wrote
+        return str(self.args[0] if self.name == "parametrize" else self.name)
+
 
 # A generic parameter designating an object to which a Mark may
 # be applied -- a test function (callable) or class.
@@ -370,17 +376,18 @@ def get_unpacked_marks(obj: object) -> Iterable[Mark]:
 
 def get_mro_marks(cls: type):
     if cls is object or cls is None or hasattr(cls, "mro_markers"):
-        return getattr(cls, "mro_markers", [])
+        return getattr(cls, "mro_markers", {})
 
-    # markers = list(mark for mark in get_unpacked_marks(cls) if mark.name != "parametrize")
-    markers = list(mark for mark in get_unpacked_marks(cls))
+    mro_markers = {mark.unique_name: mark for mark in get_unpacked_marks(cls)}
     for parent_obj in cls.__mro__[1:]:
         if parent_obj is not object:
-            markers.extend(get_mro_marks(parent_obj))
+            for unique_name, mark in get_mro_marks(parent_obj).items():
+                if unique_name not in mro_markers:
+                    mro_markers[unique_name] = mark
 
     # To not extract the marks for each item's classes, I store the variable in "cls" as variable cached.
-    setattr(cls, "mro_markers", list({str(mark): mark for mark in markers}.values()))
-    return markers
+    setattr(cls, "mro_markers", mro_markers)
+    return mro_markers
 
 
 def normalize_mark_list(
diff --git a/src/_pytest/nodes.py b/src/_pytest/nodes.py
index 6cffff1eb..ac0468ec1 100644
--- a/src/_pytest/nodes.py
+++ b/src/_pytest/nodes.py
@@ -382,9 +382,9 @@ class Node(metaclass=NodeMeta):
         for node in reversed(self.listchain()):
             for mark in node.own_markers:
                 if name is None or getattr(mark, "name", None) == name:
-                    mark_to_str = str(mark)
-                    if mark_to_str not in duplicate_marks:
-                        duplicate_marks[mark_to_str] = mark
+                    mark_to_name = str(mark)
+                    if mark_to_name not in duplicate_marks:
+                        duplicate_marks[mark_to_name] = mark
                         yield node, mark
 
     @overload
diff --git a/src/_pytest/python.py b/src/_pytest/python.py
index 516bcf4ed..7491df35a 100644
--- a/src/_pytest/python.py
+++ b/src/_pytest/python.py
@@ -1620,7 +1620,12 @@ class Function(PyobjMixin, nodes.Item):
         self.keywords.update(self.obj.__dict__)
         self.own_markers.extend(get_unpacked_marks(self.obj))
         if self.cls:
-            self.own_markers.extend(get_mro_marks(self.cls))
+            self.own_markers = list(
+                dict(
+                    get_mro_marks(self.cls),
+                    **{mark.unique_name: mark for mark in self.own_markers},
+                ).values()
+            )
         if callspec:
             self.callspec = callspec
             # this is total hostile and a mess
diff --git a/testing/test_mark.py b/testing/test_mark.py
index 9eecdb59c..9aab5596a 100644
--- a/testing/test_mark.py
+++ b/testing/test_mark.py
@@ -1130,6 +1130,7 @@ def test_marker_expr_eval_failure_handling(pytester: Pytester, expr) -> None:
 
 
 def test_markers_from_multiple_inheritances(pytester: Pytester) -> None:
+    # https://github.com/pytest-dev/pytest/issues/7792
     pytester.makepyfile(
         """
         import pytest
@@ -1150,3 +1151,34 @@ def test_markers_from_multiple_inheritances(pytester: Pytester) -> None:
     )
     result = pytester.inline_run()
     result.assertoutcome(passed=1)
+
+
+def test_duplicate_fixtures_in_same_class(pytester: Pytester) -> None:
+    # https://github.com/pytest-dev/pytest/issues/9175
+    pytester.makepyfile(
+        """
+        from typing import Any
+
+        import pytest
+
+
+        @pytest.fixture
+        def some_fixture(request) -> Any:
+            return request.param
+
+
+        # I apply to all test methods
+        @pytest.mark.parametrize("some_fixture", [{"b": "b"}], indirect=True)
+        class TestMultiParameterization:
+            # I apply to just this one test method
+            @pytest.mark.parametrize("some_fixture", [{"a": "a"}], indirect=True)
+            def test_local_some_fixture(self, some_fixture: Any) -> None:
+                assert "a" in some_fixture
+
+            def test_global_some_fixture(self, some_fixture: Any) -> None:
+                assert "b" in some_fixture
+
+        """
+    )
+    result = pytester.inline_run()
+    result.assertoutcome(passed=2)