diff --git a/sklearn/preprocessing/_function_transformer.py b/sklearn/preprocessing/_function_transformer.py
index f3d98903f8571..a4f5448a0922c 100644
--- a/sklearn/preprocessing/_function_transformer.py
+++ b/sklearn/preprocessing/_function_transformer.py
@@ -202,7 +202,8 @@ def fit(self, X, y=None):
 
         Parameters
         ----------
-        X : array-like, shape (n_samples, n_features)
+        X : {array-like, sparse-matrix} of shape (n_samples, n_features) \
+                if `validate=True` else any object that `func` can handle
             Input array.
 
         y : Ignored
@@ -224,7 +225,8 @@ def transform(self, X):
 
         Parameters
         ----------
-        X : array-like, shape (n_samples, n_features)
+        X : {array-like, sparse-matrix} of shape (n_samples, n_features) \
+                if `validate=True` else any object that `func` can handle
             Input array.
 
         Returns
@@ -240,7 +242,8 @@ def inverse_transform(self, X):
 
         Parameters
         ----------
-        X : array-like, shape (n_samples, n_features)
+        X : {array-like, sparse-matrix} of shape (n_samples, n_features) \
+                if `validate=True` else any object that `inverse_func` can handle
             Input array.
 
         Returns