diff --git a/semialign/semialign.cabal b/semialign/semialign.cabal
index 0777065..6d56f02 100644
--- a/semialign/semialign.cabal
+++ b/semialign/semialign.cabal
@@ -75,6 +75,7 @@ library
     , tagged                >=0.8.6    && <0.9
     , unordered-containers  >=0.2.8.0  && <0.3
     , vector                >=0.12.0.2 && <0.13
+    , witherable-class      >=0        && <0.1
 
   -- base shims
   if !impl(ghc >=8.2)
diff --git a/semialign/src/Data/Semialign/Internal.hs b/semialign/src/Data/Semialign/Internal.hs
index 7f07ebf..803ba12 100644
--- a/semialign/src/Data/Semialign/Internal.hs
+++ b/semialign/src/Data/Semialign/Internal.hs
@@ -17,13 +17,13 @@ import Data.Functor.Product              (Product (..))
 import Data.Hashable                     (Hashable (..))
 import Data.HashMap.Strict               (HashMap)
 import Data.List.NonEmpty                (NonEmpty (..))
-import Data.Maybe                        (catMaybes)
 import Data.Proxy                        (Proxy (..))
 import Data.Semigroup                    (Option (..), Semigroup (..))
 import Data.Sequence                     (Seq)
 import Data.Tagged                       (Tagged (..))
 import Data.Vector.Fusion.Stream.Monadic (Step (..), Stream (..))
 import Data.Vector.Generic               (Vector, empty, stream, unstream)
+import Data.Witherable.Class             (Filterable, catMaybes)
 
 import qualified Data.HashMap.Strict               as HM
 import qualified Data.List.NonEmpty                as NE
@@ -744,17 +744,17 @@ padZipWith :: (Semialign f) => (Maybe a -> Maybe b -> c) -> f a -> f b -> f c
 padZipWith f xs ys = uncurry f <$> padZip xs ys
 
 -- | Left-padded 'zipWith'.
-lpadZipWith :: (Maybe a -> b -> c) -> [a] -> [b] -> [c]
+lpadZipWith :: (Semialign f, Filterable f) => (Maybe a -> b -> c) -> f a -> f b -> f c
 lpadZipWith f xs ys = catMaybes $ padZipWith (\x y -> f x <$> y) xs ys
 
 -- | Left-padded 'zip'.
-lpadZip :: [a] -> [b] -> [(Maybe a, b)]
+lpadZip :: (Semialign f, Filterable f) => f a -> f b -> f (Maybe a, b)
 lpadZip = lpadZipWith (,)
 
 -- | Right-padded 'zipWith'.
-rpadZipWith :: (a -> Maybe b -> c) -> [a] -> [b] -> [c]
+rpadZipWith :: (Semialign f, Filterable f) => (a -> Maybe b -> c) -> f a -> f b -> f c
 rpadZipWith f xs ys = lpadZipWith (flip f) ys xs
 
 -- | Right-padded 'zip'.
-rpadZip :: [a] -> [b] -> [(a, Maybe b)]
+rpadZip :: (Semialign f, Filterable f) => f a -> f b -> f (a, Maybe b)
 rpadZip = rpadZipWith (,)