diff --git a/pandas/_libs/internals.pyi b/pandas/_libs/internals.pyi
index d6fac14d3ee6e..3feefe7ac8ff4 100644
--- a/pandas/_libs/internals.pyi
+++ b/pandas/_libs/internals.pyi
@@ -1,6 +1,7 @@
 from typing import (
     Iterator,
     Sequence,
+    final,
     overload,
 )
 
@@ -50,10 +51,12 @@ class SharedBlock:
 
 class NumpyBlock(SharedBlock):
     values: np.ndarray
+    @final
     def getitem_block_index(self: T, slicer: slice) -> T: ...
 
 class NDArrayBackedBlock(SharedBlock):
     values: NDArrayBackedExtensionArray
+    @final
     def getitem_block_index(self: T, slicer: slice) -> T: ...
 
 class Block(SharedBlock): ...
diff --git a/pandas/_libs/internals.pyx b/pandas/_libs/internals.pyx
index fe76075c00280..ba59c50142550 100644
--- a/pandas/_libs/internals.pyx
+++ b/pandas/_libs/internals.pyx
@@ -517,7 +517,6 @@ cdef class NumpyBlock(SharedBlock):
         #  set placement and ndim
         self.values = values
 
-    # @final  # not useful in cython, but we _would_ annotate with @final
     cpdef NumpyBlock getitem_block_index(self, slice slicer):
         """
         Perform __getitem__-like specialized to slicing along index.
@@ -540,7 +539,6 @@ cdef class NDArrayBackedBlock(SharedBlock):
         #  set placement and ndim
         self.values = values
 
-    # @final  # not useful in cython, but we _would_ annotate with @final
     cpdef NDArrayBackedBlock getitem_block_index(self, slice slicer):
         """
         Perform __getitem__-like specialized to slicing along index.
diff --git a/pandas/_typing.py b/pandas/_typing.py
index 588aa00116231..6583a9f60ee15 100644
--- a/pandas/_typing.py
+++ b/pandas/_typing.py
@@ -37,10 +37,7 @@
 # and use a string literal forward reference to it in subsequent types
 # https://mypy.readthedocs.io/en/latest/common_issues.html#import-cycles
 if TYPE_CHECKING:
-    from typing import (
-        TypedDict,
-        final,
-    )
+    from typing import TypedDict
 
     import numpy.typing as npt
 
@@ -76,8 +73,6 @@
     from pandas.tseries.offsets import DateOffset
 else:
     npt: Any = None
-    # typing.final does not exist until py38
-    final = lambda x: x
     # typing.TypedDict does not exist until py38
     TypedDict = dict
 
diff --git a/pandas/core/base.py b/pandas/core/base.py
index 430f1b57f0b87..285b7cd4f3a94 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -13,6 +13,7 @@
     Literal,
     TypeVar,
     cast,
+    final,
 )
 
 import numpy as np
@@ -24,7 +25,6 @@
     FrameOrSeries,
     IndexLabel,
     Shape,
-    final,
     npt,
 )
 from pandas.compat import PYPY
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 877ccc56fe384..c63aeb736d16a 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -18,6 +18,7 @@
     Mapping,
     Sequence,
     cast,
+    final,
     overload,
 )
 import warnings
@@ -54,7 +55,6 @@
     TimedeltaConvertibleTypes,
     TimestampConvertibleTypes,
     ValueKeyFunc,
-    final,
     npt,
 )
 from pandas.compat._optional import import_optional_dependency
diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index c5609672a9e5a..d3a86fa5950ed 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -29,6 +29,7 @@ class providing the base-class of operations.
     TypeVar,
     Union,
     cast,
+    final,
 )
 import warnings
 
@@ -49,7 +50,6 @@ class providing the base-class of operations.
     RandomState,
     Scalar,
     T,
-    final,
 )
 from pandas.compat.numpy import function as nv
 from pandas.errors import AbstractMethodError
diff --git a/pandas/core/groupby/grouper.py b/pandas/core/groupby/grouper.py
index d12366caa44e3..3307558deec33 100644
--- a/pandas/core/groupby/grouper.py
+++ b/pandas/core/groupby/grouper.py
@@ -4,7 +4,10 @@
 """
 from __future__ import annotations
 
-from typing import Hashable
+from typing import (
+    Hashable,
+    final,
+)
 import warnings
 
 import numpy as np
@@ -12,7 +15,6 @@
 from pandas._typing import (
     ArrayLike,
     FrameOrSeries,
-    final,
 )
 from pandas.errors import InvalidIndexError
 from pandas.util._decorators import cache_readonly
diff --git a/pandas/core/groupby/ops.py b/pandas/core/groupby/ops.py
index ed142ae7a890c..36fbda5974ea0 100644
--- a/pandas/core/groupby/ops.py
+++ b/pandas/core/groupby/ops.py
@@ -14,6 +14,7 @@
     Hashable,
     Iterator,
     Sequence,
+    final,
     overload,
 )
 
@@ -31,7 +32,6 @@
     F,
     FrameOrSeries,
     Shape,
-    final,
     npt,
 )
 from pandas.errors import AbstractMethodError
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index d369624d30cdf..044cdff2e0ba7 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -13,6 +13,7 @@
     Sequence,
     TypeVar,
     cast,
+    final,
     overload,
 )
 import warnings
@@ -44,7 +45,6 @@
     F,
     Shape,
     T,
-    final,
     npt,
 )
 from pandas.compat.numpy import function as nv
diff --git a/pandas/core/indexes/datetimelike.py b/pandas/core/indexes/datetimelike.py
index fef1d965eb534..07c6a84f75302 100644
--- a/pandas/core/indexes/datetimelike.py
+++ b/pandas/core/indexes/datetimelike.py
@@ -11,6 +11,7 @@
     Sequence,
     TypeVar,
     cast,
+    final,
 )
 import warnings
 
@@ -28,7 +29,6 @@
     Tick,
     parsing,
 )
-from pandas._typing import final
 from pandas.compat.numpy import function as nv
 from pandas.util._decorators import (
     Appender,
diff --git a/pandas/core/internals/base.py b/pandas/core/internals/base.py
index 2bb14efad1ce7..0ee22200ed495 100644
--- a/pandas/core/internals/base.py
+++ b/pandas/core/internals/base.py
@@ -4,12 +4,14 @@
 """
 from __future__ import annotations
 
-from typing import TypeVar
+from typing import (
+    TypeVar,
+    final,
+)
 
 from pandas._typing import (
     DtypeObj,
     Shape,
-    final,
 )
 from pandas.errors import AbstractMethodError
 
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index 139eef5b05d11..294f7c2d13593 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -9,6 +9,7 @@
     Iterable,
     Sequence,
     cast,
+    final,
 )
 import warnings
 
@@ -28,7 +29,6 @@
     DtypeObj,
     F,
     Shape,
-    final,
 )
 from pandas.util._decorators import cache_readonly
 from pandas.util._validators import validate_bool_kwarg
@@ -312,17 +312,6 @@ def getitem_block(self, slicer) -> Block:
 
         return type(self)(new_values, new_mgr_locs, self.ndim)
 
-    def getitem_block_index(self, slicer: slice) -> Block:
-        """
-        Perform __getitem__-like specialized to slicing along index.
-
-        Assumes self.ndim == 2
-        """
-        # error: Invalid index type "Tuple[ellipsis, slice]" for
-        # "Union[ndarray, ExtensionArray]"; expected type "Union[int, slice, ndarray]"
-        new_values = self.values[..., slicer]  # type: ignore[index]
-        return type(self)(new_values, self._mgr_locs, ndim=self.ndim)
-
     @final
     def getitem_block_columns(self, slicer, new_mgr_locs: BlockPlacement) -> Block:
         """
@@ -1557,6 +1546,18 @@ def _slice(self, slicer):
 
         return self.values[slicer]
 
+    @final
+    def getitem_block_index(self, slicer: slice) -> ExtensionBlock:
+        """
+        Perform __getitem__-like specialized to slicing along index.
+
+        Assumes self.ndim == 2
+        """
+        # error: Invalid index type "Tuple[ellipsis, slice]" for
+        # "Union[ndarray, ExtensionArray]"; expected type "Union[int, slice, ndarray]"
+        new_values = self.values[..., slicer]  # type: ignore[index]
+        return type(self)(new_values, self._mgr_locs, ndim=self.ndim)
+
     def fillna(
         self, value, limit=None, inplace: bool = False, downcast=None
     ) -> list[Block]:
@@ -1661,8 +1662,6 @@ def _unstack(self, unstacker, fill_value, new_placement):
 class NumpyBlock(libinternals.NumpyBlock, Block):
     values: np.ndarray
 
-    getitem_block_index = libinternals.NumpyBlock.getitem_block_index
-
 
 class NumericBlock(NumpyBlock):
     __slots__ = ()
@@ -1675,7 +1674,6 @@ class NDArrayBackedExtensionBlock(libinternals.NDArrayBackedBlock, EABackedBlock
     """
 
     values: NDArrayBackedExtensionArray
-    getitem_block_index = libinternals.NDArrayBackedBlock.getitem_block_index
 
     @property
     def is_view(self) -> bool:
diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index cf71bcfffc264..b9a75a6917140 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -7,6 +7,7 @@
     Callable,
     Hashable,
     Literal,
+    final,
     no_type_check,
 )
 
@@ -27,7 +28,6 @@
     T,
     TimedeltaConvertibleTypes,
     TimestampConvertibleTypes,
-    final,
     npt,
 )
 from pandas.compat.numpy import function as nv
diff --git a/pandas/io/parsers/base_parser.py b/pandas/io/parsers/base_parser.py
index 980c75b370bd5..5714bbab016c8 100644
--- a/pandas/io/parsers/base_parser.py
+++ b/pandas/io/parsers/base_parser.py
@@ -12,6 +12,7 @@
     Iterable,
     Sequence,
     cast,
+    final,
 )
 import warnings
 
@@ -26,7 +27,6 @@
     ArrayLike,
     DtypeArg,
     FilePathOrBuffer,
-    final,
 )
 from pandas.errors import (
     ParserError,