diff --git a/stdlib/itertools.pyi b/stdlib/itertools.pyi
index 55f9c92d8..881fb236b 100644
--- a/stdlib/itertools.pyi
+++ b/stdlib/itertools.pyi
@@ -10,6 +10,7 @@ _T = TypeVar("_T")
 _S = TypeVar("_S")
 _N = TypeVar("_N", int, float, SupportsFloat, SupportsInt, SupportsIndex, SupportsComplex)
 _T_co = TypeVar("_T_co", covariant=True)
+_S_co = TypeVar("_S_co", covariant=True)
 _T1 = TypeVar("_T1")
 _T2 = TypeVar("_T2")
 _T3 = TypeVar("_T3")
@@ -84,13 +85,13 @@ class filterfalse(Iterator[_T]):
     def __iter__(self) -> Self: ...
     def __next__(self) -> _T: ...
 
-class groupby(Iterator[tuple[_T, Iterator[_S]]], Generic[_T, _S]):
+class groupby(Iterator[tuple[_T_co, Iterator[_S_co]]], Generic[_T_co, _S_co]):
     @overload
     def __new__(cls, iterable: Iterable[_T1], key: None = None) -> groupby[_T1, _T1]: ...
     @overload
     def __new__(cls, iterable: Iterable[_T1], key: Callable[[_T1], _T2]) -> groupby[_T2, _T1]: ...
     def __iter__(self) -> Self: ...
-    def __next__(self) -> tuple[_T, Iterator[_S]]: ...
+    def __next__(self) -> tuple[_T_co, Iterator[_S_co]]: ...
 
 class islice(Iterator[_T]):
     @overload
diff --git a/test_cases/stdlib/itertools/check_itertools_recipes.py b/test_cases/stdlib/itertools/check_itertools_recipes.py
index b74d92ea5..340811eec 100644
--- a/test_cases/stdlib/itertools/check_itertools_recipes.py
+++ b/test_cases/stdlib/itertools/check_itertools_recipes.py
@@ -9,7 +9,7 @@ import collections
 import math
 import operator
 import sys
-from itertools import chain, combinations, count, cycle, filterfalse, islice, repeat, starmap, tee, zip_longest
+from itertools import chain, combinations, count, cycle, filterfalse, groupby, islice, repeat, starmap, tee, zip_longest
 from typing import Any, Callable, Hashable, Iterable, Iterator, Sequence, Tuple, Type, TypeVar, Union, overload
 from typing_extensions import Literal, TypeAlias, TypeVarTuple, Unpack
 
@@ -272,6 +272,15 @@ def unique_everseen(iterable: Iterable[_T], key: Callable[[_T], Hashable] | None
         #      yield from dict(zip(map(key, t1), t2)).values()
 
 
+# Slightly adapted from the docs recipe; a one-liner was a bit much for pyright
+def unique_justseen(iterable: Iterable[_T], key: Callable[[_T], bool] | None = None) -> Iterator[_T]:
+    "List unique elements, preserving order. Remember only the element just seen."
+    # unique_justseen('AAAABBBCCDAABBB') --> A B C D A B
+    # unique_justseen('ABBcCAD', str.lower) --> A B c A D
+    g: groupby[_T | bool, _T] = groupby(iterable, key)
+    return map(next, map(operator.itemgetter(1), g))
+
+
 def powerset(iterable: Iterable[_T]) -> Iterator[tuple[_T, ...]]:
     "powerset([1,2,3]) --> () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)"
     s = list(iterable)