diff --git a/master_changes.md b/master_changes.md
index c481f0530db..2e4bad309b1 100644
--- a/master_changes.md
+++ b/master_changes.md
@@ -81,6 +81,7 @@ users)
 ## Sandbox
 
 ## VCS
+  * Check the status of git submodules when checking if a repository is up-to-date [#6132 @kit-ty-kate]
 
 ## Build
  * Synchronise opam-core.opam with opam-repository changes [#6043 @dra27]
diff --git a/src/repository/opamGit.ml b/src/repository/opamGit.ml
index c30f66a3162..7c7b080cb04 100644
--- a/src/repository/opamGit.ml
+++ b/src/repository/opamGit.ml
@@ -216,7 +216,19 @@ module VCS : OpamVCS.VCS = struct
                    @ List.map OpamFilename.SubPath.to_string
                      (OpamStd.Option.to_list subpath))
     @@> function
-    | { OpamProcess.r_code = 0; _ } -> Done true
+    | { OpamProcess.r_code = 0; _ } ->
+      git repo_root ["submodule"; "status"; "--recursive"] @@> fun r ->
+      if r.r_code = 0 &&
+         (* NOTE: We check the first character of each lines of the output
+            to verify that every submodules are in their expected state.
+            The git submodule manual states:
+            Each SHA-1 will possibly be prefixed with - if the submodule is
+            not initialized, + if the currently checked out submodule commit
+            does not match the SHA-1 found in the index of the containing
+            repository and U if the submodule has merge conflicts. *)
+         List.for_all (fun s -> String.length s > 0 && s.[0] = ' ') r.r_stdout
+      then Done true
+      else (OpamProcess.cleanup ~force:true r; Done false)
     | { OpamProcess.r_code = 1; _ } as r ->
       OpamProcess.cleanup ~force:true r; Done false
     | r -> OpamSystem.process_error r