diff --git a/ChangeLog.md b/ChangeLog.md
index a55e5e1e8e..4da6836ef1 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -105,6 +105,10 @@ Behavior changes:
   can be disabled via the `hide-source-paths` configuration option in
   `stack.yaml`. See [#3784](https://github.com/commercialhaskell/stack/issues/3784)
 
+* Stack will reconfigure a package if you modify your `PATH` environment
+  variable. See
+  [#3138](https://github.com/commercialhaskell/stack/issues/3138).
+
 Other enhancements:
 
 * Defer loading up of files for local packages. This allows us to get
diff --git a/src/Stack/Build/ConstructPlan.hs b/src/Stack/Build/ConstructPlan.hs
index 35fd52d50e..d2d29970d3 100644
--- a/src/Stack/Build/ConstructPlan.hs
+++ b/src/Stack/Build/ConstructPlan.hs
@@ -49,6 +49,7 @@ import           Stack.Types.NamedComponent
 import           Stack.Types.Package
 import           Stack.Types.SourceMap
 import           Stack.Types.Version
+import           System.Environment (lookupEnv)
 import           System.IO (putStrLn)
 import           RIO.PrettyPrint
 import           RIO.Process (findExecutable, HasProcessContext (..))
@@ -124,6 +125,7 @@ data Ctx = Ctx
     , wanted         :: !(Set PackageName)
     , localNames     :: !(Set PackageName)
     , mcurator       :: !(Maybe Curator)
+    , pathEnvVar     :: !Text
     }
 
 instance HasPlatform Ctx
@@ -187,7 +189,8 @@ constructPlan baseConfigOpts0 localDumpPkgs loadPackage0 sourceMap installedMap
 
     let onTarget = void . addDep
     let inner = mapM_ onTarget $ Map.keys (smtTargets $ smTargets sourceMap)
-    let ctx = mkCtx econfig globalCabalVersion sources mcur
+    pathEnvVar' <- liftIO $ maybe mempty T.pack <$> lookupEnv "PATH"
+    let ctx = mkCtx econfig globalCabalVersion sources mcur pathEnvVar'
     ((), m, W efinals installExes dirtyReason warnings parents) <-
         liftIO $ runRWST inner ctx M.empty
     mapM_ (logWarn . RIO.display) (warnings [])
@@ -226,7 +229,7 @@ constructPlan baseConfigOpts0 localDumpPkgs loadPackage0 sourceMap installedMap
   where
     hasBaseInDeps = Map.member (mkPackageName "base") (smDeps sourceMap)
 
-    mkCtx econfig globalCabalVersion sources mcur = Ctx
+    mkCtx econfig globalCabalVersion sources mcur pathEnvVar' = Ctx
         { baseConfigOpts = baseConfigOpts0
         , loadPackage = \x y z -> runRIO econfig $
             applyForceCustomBuild globalCabalVersion <$> loadPackage0 x y z
@@ -236,6 +239,7 @@ constructPlan baseConfigOpts0 localDumpPkgs loadPackage0 sourceMap installedMap
         , wanted = Map.keysSet (smtTargets $ smTargets sourceMap)
         , localNames = Map.keysSet (smProject sourceMap)
         , mcurator = mcur
+        , pathEnvVar = pathEnvVar'
         }
 
     prunedGlobalDeps = flip Map.mapMaybe (smGlobal sourceMap) $ \gp ->
@@ -788,6 +792,7 @@ checkDirtiness ps installed package present = do
                     PSFilePath lp -> Set.map (encodeUtf8 . renderComponent) $ lpComponents lp
                     PSRemote{} -> Set.empty
             , configCachePkgSrc = toCachePkgSrc ps
+            , configCachePathEnvVar = pathEnvVar ctx
             }
         config = view configL ctx
     mreason <-
diff --git a/src/Stack/Build/Execute.hs b/src/Stack/Build/Execute.hs
index 32411e8ca0..d1a200a33c 100644
--- a/src/Stack/Build/Execute.hs
+++ b/src/Stack/Build/Execute.hs
@@ -82,7 +82,7 @@ import           Stack.Types.NamedComponent
 import           Stack.Types.Package
 import           Stack.Types.Version
 import qualified System.Directory as D
-import           System.Environment (getExecutablePath)
+import           System.Environment (getExecutablePath, lookupEnv)
 import           System.Exit (ExitCode (..))
 import qualified System.FilePath as FP
 import           System.IO (stderr, stdout)
@@ -209,6 +209,8 @@ data ExecuteEnv = ExecuteEnv
     -- Setup.hs built.
     , eeLargestPackageName :: !(Maybe Int)
     -- ^ For nicer interleaved output: track the largest package name size
+    , eePathEnvVar :: !Text
+    -- ^ Value of the PATH environment variable
     }
 
 buildSetupArgs :: [String]
@@ -341,6 +343,7 @@ withExecuteEnv bopts boptsCli baseConfigOpts locals globalPackages snapshotPacka
         localPackagesTVar <- liftIO $ newTVarIO (toDumpPackagesByGhcPkgId localPackages)
         logFilesTChan <- liftIO $ atomically newTChan
         let totalWanted = length $ filter lpWanted locals
+        pathEnvVar <- liftIO $ maybe mempty T.pack <$> lookupEnv "PATH"
         inner ExecuteEnv
             { eeBuildOpts = bopts
             , eeBuildOptsCLI = boptsCli
@@ -366,6 +369,7 @@ withExecuteEnv bopts boptsCli baseConfigOpts locals globalPackages snapshotPacka
             , eeLogFiles = logFilesTChan
             , eeCustomBuilt = customBuiltRef
             , eeLargestPackageName = mlargestPackageName
+            , eePathEnvVar = pathEnvVar
             } `finally` dumpLogs logFilesTChan totalWanted
   where
     toDumpPackagesByGhcPkgId = Map.fromList . map (\dp -> (dpGhcPkgId dp, dp))
@@ -824,6 +828,7 @@ getConfigCache ExecuteEnv {..} task@Task {..} installedMap enableTest enableBenc
                     TTLocalMutable lp -> Set.map (encodeUtf8 . renderComponent) $ lpComponents lp
                     TTRemotePackage{} -> Set.empty
             , configCachePkgSrc = taskCachePkgSrc
+            , configCachePathEnvVar = eePathEnvVar
             }
         allDepsMap = Map.union missing' taskPresent
     return (allDepsMap, cache)
diff --git a/src/Stack/Storage.hs b/src/Stack/Storage.hs
index 5554fcfa97..a926688c0a 100644
--- a/src/Stack/Storage.hs
+++ b/src/Stack/Storage.hs
@@ -64,6 +64,7 @@ ConfigCacheParent sql="config_cache"
   type ConfigCacheType default=''
   pkgSrc CachePkgSrc default=''
   active Bool default=0
+  pathEnvVar Text default=''
   UniqueConfigCacheParent directory type sql="unique_config_cache"
   deriving Show
 
@@ -199,6 +200,7 @@ readConfigCache (Entity parentId ConfigCacheParent {..}) = do
     configCacheComponents <-
         Set.fromList . map (configCacheComponentValue . entityVal) <$>
         selectList [ConfigCacheComponentParent ==. parentId] []
+    let configCachePathEnvVar = configCacheParentPathEnvVar
     return ConfigCache {..}
 
 -- | Load 'ConfigCache' from the database.
@@ -235,6 +237,7 @@ saveConfigCache key@(UniqueConfigCacheParent dir type_) new =
                             , configCacheParentType = type_
                             , configCacheParentPkgSrc = configCachePkgSrc new
                             , configCacheParentActive = True
+                            , configCacheParentPathEnvVar = configCachePathEnvVar new
                             }
                 Just parentEntity@(Entity parentId _) -> do
                     old <- readConfigCache parentEntity
diff --git a/src/Stack/Types/Build.hs b/src/Stack/Types/Build.hs
index 97bab17f0e..7a384decce 100644
--- a/src/Stack/Types/Build.hs
+++ b/src/Stack/Types/Build.hs
@@ -391,6 +391,8 @@ data ConfigCache = ConfigCache
       -- here, as it's not a configure option (just a build option), but this
       -- is a convenient way to force compilation when the components change.
     , configCachePkgSrc :: !CachePkgSrc
+    , configCachePathEnvVar :: !Text
+    -- ^ Value of the PATH env var, see <https://github.com/commercialhaskell/stack/issues/3138>
     }
     deriving (Generic, Eq, Show, Data, Typeable)
 instance NFData ConfigCache