diff --git a/doc/source/whatsnew/v2.0.0.rst b/doc/source/whatsnew/v2.0.0.rst
index 7cf88a642f511..7675379c0b41b 100644
--- a/doc/source/whatsnew/v2.0.0.rst
+++ b/doc/source/whatsnew/v2.0.0.rst
@@ -761,6 +761,8 @@ Other API changes
 - The levels of the index of the :class:`Series` returned from ``Series.sparse.from_coo`` now always have dtype ``int32``. Previously they had dtype ``int64`` (:issue:`50926`)
 - :func:`to_datetime` with ``unit`` of either "Y" or "M" will now raise if a sequence contains a non-round ``float`` value, matching the ``Timestamp`` behavior (:issue:`50301`)
 - The methods :meth:`Series.round`, :meth:`DataFrame.__invert__`, :meth:`Series.__invert__`, :meth:`DataFrame.swapaxes`, :meth:`DataFrame.first`, :meth:`DataFrame.last`, :meth:`Series.first`, :meth:`Series.last` and :meth:`DataFrame.align` will now always return new objects (:issue:`51032`)
+- Removed :attr:`Grouper.groups`, which would have raised ``AttributeError`` if accessed (:issue:`51170`)
+-
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_200.deprecations:
diff --git a/pandas/core/groupby/grouper.py b/pandas/core/groupby/grouper.py
index d77ad59a4bb82..2f2900cd6f11d 100644
--- a/pandas/core/groupby/grouper.py
+++ b/pandas/core/groupby/grouper.py
@@ -268,7 +268,6 @@ def __init__(
         self.sort = sort
         self.dropna = dropna
 
-        self.grouper = None
         self._gpr_index = None
         self.obj = None
         self.indexer = None
@@ -328,7 +327,7 @@ def _set_grouper(self, obj: NDFrame, sort: bool = False) -> None:
         if self.key is not None and self.level is not None:
             raise ValueError("The Grouper cannot specify both a key and a level!")
 
-        # Keep self.grouper value before overriding
+        # Keep self._grouper value before overriding
         if self._grouper is None:
             # TODO: What are we assuming about subsequent calls?
             self._grouper = self._gpr_index
@@ -387,12 +386,6 @@ def _set_grouper(self, obj: NDFrame, sort: bool = False) -> None:
         self.obj = obj  # type: ignore[assignment]
         self._gpr_index = ax
 
-    @final
-    @property
-    def groups(self):
-        # error: "None" has no attribute "groups"
-        return self.grouper.groups  # type: ignore[attr-defined]
-
     @final
     def __repr__(self) -> str:
         attrs_list = (