diff --git a/CHANGES.md b/CHANGES.md
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,9 @@
+## [0.2.13.0]
+
+* [Add `HashMap.compose`.](https://github.com/haskell-unordered-containers/unordered-containers/pull/299) Thanks Alexandre Esteves.
+
+[0.2.13.0]: https://github.com/haskell-unordered-containers/unordered-containers/compare/v0.2.12.0...v0.2.13.0
+
 ## [0.2.12.0]
 
 * Add `HashMap.isSubmapOf[By]` and `HashSet.isSubsetOf`. Thanks Sven Keidel. ([#282])
@@ -7,7 +13,7 @@
 * Documentation improvements in `Data.HashSet`, including a beginner-friendly
   introduction. Thanks Matt Renaud. ([#267])
 
-* `HashMap[.Strict].alterF`: Skip key deletion for absent keys. ([#288])
+* `HashMap.alterF`: Skip key deletion for absent keys. ([#288])
 
 * Remove custom `unsafeShift{L,R}` definitions. ([#281])
 
diff --git a/Data/HashMap/Internal.hs b/Data/HashMap/Internal.hs
--- a/Data/HashMap/Internal.hs
+++ b/Data/HashMap/Internal.hs
@@ -60,6 +60,9 @@
     , unionWithKey
     , unions
 
+    -- ** Compose
+    , compose
+
       -- * Transformations
     , map
     , mapWithKey
@@ -418,7 +421,7 @@
 #endif
 
 -- | The ordering is total and consistent with the `Eq` instance. However,
--- nothing else about the ordering is specified, and it may change from 
+-- nothing else about the ordering is specified, and it may change from
 -- version to version of either this package or of hashable.
 instance (Ord k, Ord v) => Ord (HashMap k v) where
     compare = cmp compare compare
@@ -1678,6 +1681,29 @@
 unions :: (Eq k, Hashable k) => [HashMap k v] -> HashMap k v
 unions = L.foldl' union empty
 {-# INLINE unions #-}
+
+
+------------------------------------------------------------------------
+-- * Compose
+
+-- | Relate the keys of one map to the values of
+-- the other, by using the values of the former as keys for lookups
+-- in the latter.
+--
+-- Complexity: \( O (n * \log(m)) \), where \(m\) is the size of the first argument
+--
+-- >>> compose (fromList [('a', "A"), ('b', "B")]) (fromList [(1,'a'),(2,'b'),(3,'z')])
+-- fromList [(1,"A"),(2,"B")]
+--
+-- @
+-- ('compose' bc ab '!?') = (bc '!?') <=< (ab '!?')
+-- @
+--
+-- @since UNRELEASED
+compose :: (Eq b, Hashable b) => HashMap b c -> HashMap a b -> HashMap a c
+compose bc !ab
+  | null bc = empty
+  | otherwise = mapMaybe (bc !?) ab
 
 ------------------------------------------------------------------------
 -- * Transformations
diff --git a/Data/HashMap/Internal/Strict.hs b/Data/HashMap/Internal/Strict.hs
--- a/Data/HashMap/Internal/Strict.hs
+++ b/Data/HashMap/Internal/Strict.hs
@@ -74,6 +74,9 @@
     , unionWithKey
     , unions
 
+    -- ** Compose
+    , compose
+
       -- * Transformations
     , map
     , mapWithKey
diff --git a/Data/HashMap/Lazy.hs b/Data/HashMap/Lazy.hs
--- a/Data/HashMap/Lazy.hs
+++ b/Data/HashMap/Lazy.hs
@@ -59,6 +59,9 @@
     , unionWithKey
     , unions
 
+    -- ** Compose
+    , compose
+
       -- * Transformations
     , map
     , mapWithKey
diff --git a/Data/HashMap/Strict.hs b/Data/HashMap/Strict.hs
--- a/Data/HashMap/Strict.hs
+++ b/Data/HashMap/Strict.hs
@@ -58,6 +58,9 @@
     , unionWithKey
     , unions
 
+    -- ** Compose
+    , compose
+
       -- * Transformations
     , map
     , mapWithKey
diff --git a/unordered-containers.cabal b/unordered-containers.cabal
--- a/unordered-containers.cabal
+++ b/unordered-containers.cabal
@@ -1,5 +1,5 @@
 name:           unordered-containers
-version:        0.2.12.0
+version:        0.2.13.0
 synopsis:       Efficient hashing-based container types
 description:
   Efficient hashing-based container types.  The containers have been