diff --git a/CHANGES.md b/CHANGES.md
index 957bb63e0..00e0ceb77 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -4,6 +4,7 @@ unreleased
   + merlin binary
     - A new `WRAPPING_PREFIX` configuration directive that can be used to tell Merlin
       what to append to the current unit name in the presence of wrapping (#1788)
+    - Add `-unboxed-types` and `-no-unboxed-types` as ocaml ignored flags (#1795, fixes #1794)
 
 merlin 5.1
 ==========
diff --git a/src/kernel/mconfig.ml b/src/kernel/mconfig.ml
index 55875fa6b..4fdaaacda 100644
--- a/src/kernel/mconfig.ml
+++ b/src/kernel/mconfig.ml
@@ -457,10 +457,10 @@ let ocaml_ignored_flags = [
   "-noautolink"; "-no-check-prims"; "-nodynlink"; "-no-float-const-prop";
   "-no-keep-locs"; "-no-principal"; "-no-rectypes"; "-no-strict-formats";
   "-no-strict-sequence"; "-no-unbox-free-vars-of-clos";
-  "-no-unbox-specialised-args"; "-O2"; "-O3"; "-Oclassic"; "-opaque";
-  "-output-complete-obj"; "-output-obj"; "-p"; "-pack";
-  "-remove-unused-arguments"; "-S"; "-shared"; "-unbox-closures"; "-v";
-  "-verbose"; "-where";
+  "-no-unbox-specialised-args"; "-no-unboxed-types"; "-O2"; "-O3";
+  "-Oclassic"; "-opaque"; "-output-complete-obj"; "-output-obj"; "-p"; "-pack";
+  "-remove-unused-arguments"; "-S"; "-shared"; "-unbox-closures";
+  "-unboxed-types"; "-v"; "-verbose"; "-where";
 ]
 
 let ocaml_ignored_parametrized_flags = [
diff --git a/tests/test-dirs/errors/issue1794.t b/tests/test-dirs/errors/issue1794.t
new file mode 100644
index 000000000..b5ee24a47
--- /dev/null
+++ b/tests/test-dirs/errors/issue1794.t
@@ -0,0 +1,13 @@
+  $ $MERLIN single errors -filename main.ml -unboxed-types
+  {
+    "class": "return",
+    "value": [],
+    "notifications": []
+  }
+
+  $ $MERLIN single errors -filename main.ml -no-unboxed-types
+  {
+    "class": "return",
+    "value": [],
+    "notifications": []
+  }