diff --git a/libraries/base/changelog.md b/libraries/base/changelog.md
index df7e6c40ae67fc7dbdc0c55aed931c28a48e6263..11c3a4cbb56acfa99a228dbf57b55fbb2abe8a5a 100644
--- a/libraries/base/changelog.md
+++ b/libraries/base/changelog.md
@@ -6,6 +6,7 @@
   * The `HasField` class now supports representation polymorphism ([CLC proposal #194](https://github.com/haskell/core-libraries-committee/issues/194))
   * Make `read` accept binary integer notation ([CLC proposal #177](https://github.com/haskell/core-libraries-committee/issues/177))
   * Improve the performance of `Data.List.sort` using an improved merging strategy. Instead of `compare`, `sort` now uses `(>)` which may break *malformed* `Ord` instances ([CLC proposal #236](https://github.com/haskell/core-libraries-committee/issues/236))
+  * Add `firstA` and `secondA` to `Data.Bitraversable`. ([CLC proposal #172](https://github.com/haskell/core-libraries-committee/issues/172))
 
 ## 4.20.0.0 *TBA*
   * Deprecate `GHC.Pack` ([#21461](https://gitlab.haskell.org/ghc/ghc/-/issues/21461))
diff --git a/libraries/base/src/Data/Bitraversable.hs b/libraries/base/src/Data/Bitraversable.hs
index a0c1f2e61a6c767a26683c5244fd71c7622dd2f1..374aaf9ee3eddf3a490ab4635c3893e3e9c50588 100644
--- a/libraries/base/src/Data/Bitraversable.hs
+++ b/libraries/base/src/Data/Bitraversable.hs
@@ -18,6 +18,8 @@ module Data.Bitraversable
   , bisequenceA
   , bisequence
   , bimapM
+  , firstA
+  , secondA
   , bifor
   , biforM
   , bimapAccumL
@@ -172,6 +174,60 @@ bimapM = bitraverse
 bisequence :: (Bitraversable t, Applicative f) => t (f a) (f b) -> f (t a b)
 bisequence = bitraverse id id
 
+-- | Traverses only over the first argument.
+--
+-- @'firstA' f ≡ 'bitraverse' f 'pure'@
+
+-- ==== __Examples__
+--
+-- Basic usage:
+--
+-- >>> firstA listToMaybe (Left [])
+-- Nothing
+--
+-- >>> firstA listToMaybe (Left [1, 2, 3])
+-- Just (Left 1)
+--
+-- >>> firstA listToMaybe (Right [4, 5])
+-- Just (Right [4, 5])
+--
+-- >>> firstA listToMaybe ([1, 2, 3], [4, 5])
+-- Just (1,[4, 5])
+--
+-- >>> firstA listToMaybe ([], [4, 5])
+-- Nothing
+
+-- @since 4.21.0.0
+firstA :: Bitraversable t => Applicative f => (a -> f c) -> t a b -> f (t c b)
+firstA f = bitraverse f pure
+
+-- | Traverses only over the second argument.
+--
+-- @'secondA' f ≡ 'bitraverse' 'pure' f@
+--
+-- ==== __Examples__
+--
+-- Basic usage:
+--
+-- >>> secondA (find odd) (Left [])
+-- Just (Left [])
+--
+-- >>> secondA (find odd) (Left [1, 2, 3])
+-- Just (Left [1,2,3])
+--
+-- >>> secondA (find odd) (Right [4, 5])
+-- Just (Right 5)
+--
+-- >>> secondA (find odd) ([1, 2, 3], [4, 5])
+-- Just ([1,2,3],5)
+--
+-- >>> secondA (find odd) ([1,2,3], [4])
+-- Nothing
+--
+-- @since 4.21.0.0
+secondA :: Bitraversable t => Applicative f => (b -> f c) -> t a b -> f (t a c)
+secondA f = bitraverse pure f
+
 -- | Class laws for tuples hold only up to laziness. The
 -- Bitraversable methods are lazier than their Traversable counterparts.
 -- For example the law @'bitraverse' 'pure' ≡ 'traverse'@ does
diff --git a/testsuite/tests/interface-stability/base-exports.stdout b/testsuite/tests/interface-stability/base-exports.stdout
index 968f297ea5289bcad9f6311cd6a2ee6f97369cdd..0e8f2cb9c1c6751434858453375502ac3afdc59e 100644
--- a/testsuite/tests/interface-stability/base-exports.stdout
+++ b/testsuite/tests/interface-stability/base-exports.stdout
@@ -679,6 +679,8 @@ module Data.Bitraversable where
   bimapM :: forall (t :: * -> * -> *) (f :: * -> *) a c b d. (Bitraversable t, GHC.Internal.Base.Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f (t c d)
   bisequence :: forall (t :: * -> * -> *) (f :: * -> *) a b. (Bitraversable t, GHC.Internal.Base.Applicative f) => t (f a) (f b) -> f (t a b)
   bisequenceA :: forall (t :: * -> * -> *) (f :: * -> *) a b. (Bitraversable t, GHC.Internal.Base.Applicative f) => t (f a) (f b) -> f (t a b)
+  firstA :: forall (t :: * -> * -> *) (f :: * -> *) a c b. (Bitraversable t, GHC.Internal.Base.Applicative f) => (a -> f c) -> t a b -> f (t c b)
+  secondA :: forall (t :: * -> * -> *) (f :: * -> *) b c a. (Bitraversable t, GHC.Internal.Base.Applicative f) => (b -> f c) -> t a b -> f (t a c)
 
 module Data.Bits where
   -- Safety: Safe
diff --git a/testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs b/testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs
index ef4bcf866fa6149877f34fd9a937e58b59b29708..9a365415902e1ba64b3f0a82761391604312957a 100644
--- a/testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs
+++ b/testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs
@@ -679,6 +679,8 @@ module Data.Bitraversable where
   bimapM :: forall (t :: * -> * -> *) (f :: * -> *) a c b d. (Bitraversable t, GHC.Internal.Base.Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f (t c d)
   bisequence :: forall (t :: * -> * -> *) (f :: * -> *) a b. (Bitraversable t, GHC.Internal.Base.Applicative f) => t (f a) (f b) -> f (t a b)
   bisequenceA :: forall (t :: * -> * -> *) (f :: * -> *) a b. (Bitraversable t, GHC.Internal.Base.Applicative f) => t (f a) (f b) -> f (t a b)
+  firstA :: forall (t :: * -> * -> *) (f :: * -> *) a c b. (Bitraversable t, GHC.Internal.Base.Applicative f) => (a -> f c) -> t a b -> f (t c b)
+  secondA :: forall (t :: * -> * -> *) (f :: * -> *) b c a. (Bitraversable t, GHC.Internal.Base.Applicative f) => (b -> f c) -> t a b -> f (t a c)
 
 module Data.Bits where
   -- Safety: Safe
diff --git a/testsuite/tests/interface-stability/base-exports.stdout-mingw32 b/testsuite/tests/interface-stability/base-exports.stdout-mingw32
index b288c0684ff2e9458b6711e2ae2d8ebffc8d683d..3ee181fb052ad5d5bc8828f36b3d95ab9b264157 100644
--- a/testsuite/tests/interface-stability/base-exports.stdout-mingw32
+++ b/testsuite/tests/interface-stability/base-exports.stdout-mingw32
@@ -679,6 +679,8 @@ module Data.Bitraversable where
   bimapM :: forall (t :: * -> * -> *) (f :: * -> *) a c b d. (Bitraversable t, GHC.Internal.Base.Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f (t c d)
   bisequence :: forall (t :: * -> * -> *) (f :: * -> *) a b. (Bitraversable t, GHC.Internal.Base.Applicative f) => t (f a) (f b) -> f (t a b)
   bisequenceA :: forall (t :: * -> * -> *) (f :: * -> *) a b. (Bitraversable t, GHC.Internal.Base.Applicative f) => t (f a) (f b) -> f (t a b)
+  firstA :: forall (t :: * -> * -> *) (f :: * -> *) a c b. (Bitraversable t, GHC.Internal.Base.Applicative f) => (a -> f c) -> t a b -> f (t c b)
+  secondA :: forall (t :: * -> * -> *) (f :: * -> *) b c a. (Bitraversable t, GHC.Internal.Base.Applicative f) => (b -> f c) -> t a b -> f (t a c)
 
 module Data.Bits where
   -- Safety: Safe
diff --git a/testsuite/tests/interface-stability/base-exports.stdout-ws-32 b/testsuite/tests/interface-stability/base-exports.stdout-ws-32
index 968f297ea5289bcad9f6311cd6a2ee6f97369cdd..0e8f2cb9c1c6751434858453375502ac3afdc59e 100644
--- a/testsuite/tests/interface-stability/base-exports.stdout-ws-32
+++ b/testsuite/tests/interface-stability/base-exports.stdout-ws-32
@@ -679,6 +679,8 @@ module Data.Bitraversable where
   bimapM :: forall (t :: * -> * -> *) (f :: * -> *) a c b d. (Bitraversable t, GHC.Internal.Base.Applicative f) => (a -> f c) -> (b -> f d) -> t a b -> f (t c d)
   bisequence :: forall (t :: * -> * -> *) (f :: * -> *) a b. (Bitraversable t, GHC.Internal.Base.Applicative f) => t (f a) (f b) -> f (t a b)
   bisequenceA :: forall (t :: * -> * -> *) (f :: * -> *) a b. (Bitraversable t, GHC.Internal.Base.Applicative f) => t (f a) (f b) -> f (t a b)
+  firstA :: forall (t :: * -> * -> *) (f :: * -> *) a c b. (Bitraversable t, GHC.Internal.Base.Applicative f) => (a -> f c) -> t a b -> f (t c b)
+  secondA :: forall (t :: * -> * -> *) (f :: * -> *) b c a. (Bitraversable t, GHC.Internal.Base.Applicative f) => (b -> f c) -> t a b -> f (t a c)
 
 module Data.Bits where
   -- Safety: Safe