diff --git a/cabal-install/src/Distribution/Client/CmdRepl.hs b/cabal-install/src/Distribution/Client/CmdRepl.hs
index a8189f8e677..e243eb82974 100644
--- a/cabal-install/src/Distribution/Client/CmdRepl.hs
+++ b/cabal-install/src/Distribution/Client/CmdRepl.hs
@@ -447,6 +447,25 @@ replAction flags@NixStyleFlags{extraFlags = r@ReplFlags{..}, ..} targetStrings g
         -- unit files for components
         unit_files <- listDirectory dir
 
+        -- Order the unit files so that the find target becomes the active unit
+        let active_unit_fp :: Maybe FilePath
+            active_unit_fp = do
+              -- Get the first target selectors from the cli
+              activeTarget <- safeHead targetSelectors
+              -- Lookup the targets :: Map UnitId [(ComponentTarget, NonEmpty TargetSelector)]
+              unitId <-
+                Map.toList targets
+                  -- Keep the UnitId matching the desired target selector
+                  & find (\(_, xs) -> any (\(_, selectors) -> activeTarget `elem` selectors) xs)
+                  & fmap fst
+              -- Convert to filename (adapted from 'storePackageDirectory')
+              pure (prettyShow unitId)
+            unit_files_ordered :: [FilePath]
+            unit_files_ordered =
+              let (active_unit_files, other_units) = partition (\fp -> Just fp == active_unit_fp) unit_files
+               in -- GHC considers the last unit passed to be the active one
+                  other_units ++ active_unit_files
+
         -- run ghc --interactive with
         runProgramInvocation verbosity $
           programInvocation ghcProg' $
@@ -458,7 +477,7 @@ replAction flags@NixStyleFlags{extraFlags = r@ReplFlags{..}, ..} targetStrings g
               , show (buildSettingNumJobs (buildSettings ctx))
               ]
                 : [ ["-unit", "@" ++ dir </> unit]
-                  | unit <- unit_files
+                  | unit <- unit_files_ordered
                   , unit /= "paths"
                   ]
 
diff --git a/cabal-testsuite/PackageTests/MultiRepl/EnabledClosure/cabal.test.hs b/cabal-testsuite/PackageTests/MultiRepl/EnabledClosure/cabal.test.hs
index 54a0afeb91e..7bfea13c2bc 100644
--- a/cabal-testsuite/PackageTests/MultiRepl/EnabledClosure/cabal.test.hs
+++ b/cabal-testsuite/PackageTests/MultiRepl/EnabledClosure/cabal.test.hs
@@ -5,13 +5,7 @@ main = do
     skipUnlessGhcVersion ">= 9.4"
     -- Note: only the last package is interactive.
     -- this test should load pkg-b too.
-    res <- cabalWithStdin "v2-repl" ["--enable-multi-repl","pkg-a", "pkg-c"] ""
-
-    -- we should check that pkg-c is indeed loaded,
-    -- but currently the unit order is non-deterministic
-    -- Fix this when GHC has a way to change active unit.
-    -- TODO: ask for pkg-c unit, print Quu.quu
+    res <- cabalWithStdin "v2-repl" ["--enable-multi-repl","pkg-c", "pkg-a"] "Quu.quu"
 
     assertOutputContains "- pkg-b-0 (interactive)" res
-    -- assertOutputContains "168" res
-    return ()
+    assertOutputContains "168" res
diff --git a/cabal-testsuite/PackageTests/MultiRepl/EnabledSucc/cabal.test.hs b/cabal-testsuite/PackageTests/MultiRepl/EnabledSucc/cabal.test.hs
index 640b25d0d94..7ea2f71ea49 100644
--- a/cabal-testsuite/PackageTests/MultiRepl/EnabledSucc/cabal.test.hs
+++ b/cabal-testsuite/PackageTests/MultiRepl/EnabledSucc/cabal.test.hs
@@ -4,9 +4,5 @@ main = do
   cabalTest $ do
     skipUnlessGhcVersion ">= 9.4"
     skipIfWindows -- heisenbug, see #9103
-    -- the package order is non-deterministic.
-    -- add Bar.Bar input to test that packages are trully loaded
-    -- when GHC gets support for switching active units
-    res <- cabalWithStdin "v2-repl" ["--enable-multi-repl","pkg-a", "pkg-b"] ""
-    -- assertOutputContains "3735929054" res
-    return ()
+    res <- cabalWithStdin "v2-repl" ["--enable-multi-repl","pkg-b", "pkg-a"] "Bar.bar"
+    assertOutputContains "3735929054" res
diff --git a/doc/internal/multi-repl.md b/doc/internal/multi-repl.md
index 5f0f731e393..1e89872886a 100644
--- a/doc/internal/multi-repl.md
+++ b/doc/internal/multi-repl.md
@@ -33,11 +33,12 @@ Here are some common targets which you can specify when using `cabal`.
 
 * `all`: Build all the locally defined components.
 * `exe:haskell-language-server`: Build the executable called `haskell-language-server`
-* `lib:pkg-a lib:pkg-b`: Build the local libraries pkg-a and pkg-b.
+* `lib:pkg-a lib:pkg-b`: Build the local libraries pkg-a and pkg-b. pkg-a will be the active unit.
 * `src/Main.hs`: Build the unit which `src/Main.hs` belongs to.
 
 After enabling multi-repl, passing a target specification to `cabal repl` which
 resolves to multiple units will load all those units into a single repl session.
+The first "target" will be the active unit.
 For example:
 
 ```
@@ -203,6 +204,14 @@ At this time, the multi-repl is best used for interactive development situations
 you want to use the repl to obtain fast-feedback about your project.
 We have made sure that the multi-repl works with `ghcid` for example.
 
+When evaluating code, make sure that the code is in the scope of the active unit,
+which is the first target given on the command line. For example, to run the test suite
+entrypoint, use:
+
+```
+ghcid --command "cabal repl --enable-multi-repl test:suite lib:pkg" --test Main.main
+```
+
 # Conclusion
 
 Adding `cabal repl` support for multiple home units allows developers to easily