diff --git a/CHANGELOG.md b/CHANGELOG.md
index 765c686257..d92e2f55f1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@
 - Fixed subtype checking for record types with "@as" attributes: The subtype relationship now takes into account the compatibility of "@as" attributes between corresponding fields, ensuring correctness in runtime representation.
  https://github.com/rescript-lang/rescript-compiler/issues/6158
 - Emit directive above header comment. https://github.com/rescript-lang/rescript-compiler/pull/6172
+- Add error message to private extension. https://github.com/rescript-lang/rescript-compiler/pull/6175
 
 #### :nail_care: Polish
 
diff --git a/jscomp/build_tests/super_errors/expected/private_without_body.res.expected b/jscomp/build_tests/super_errors/expected/private_without_body.res.expected
new file mode 100644
index 0000000000..e044450570
--- /dev/null
+++ b/jscomp/build_tests/super_errors/expected/private_without_body.res.expected
@@ -0,0 +1,9 @@
+
+  We've found a bug for you!
+  /.../fixtures/private_without_body.res:1:1-9
+
+  1 │ %%private
+  2 │ let a = 2
+  3 │ 
+
+  %%private extension expects a definition as its argument. Example: %%private(let a = "Hello")
\ No newline at end of file
diff --git a/jscomp/build_tests/super_errors/fixtures/private_without_body.res b/jscomp/build_tests/super_errors/fixtures/private_without_body.res
new file mode 100644
index 0000000000..cadfcfd3a3
--- /dev/null
+++ b/jscomp/build_tests/super_errors/fixtures/private_without_body.res
@@ -0,0 +1,2 @@
+%%private
+let a = 2
diff --git a/jscomp/frontend/bs_builtin_ppx.ml b/jscomp/frontend/bs_builtin_ppx.ml
index 1001a097ac..c61c09f981 100644
--- a/jscomp/frontend/bs_builtin_ppx.ml
+++ b/jscomp/frontend/bs_builtin_ppx.ml
@@ -474,6 +474,9 @@ let rec structure_mapper (self : mapper) (stru : Ast_structure.t) =
           :: next -> (
           match payload with
           | PStr work ->
+            if List.length work = 0 then
+              Location.raise_errorf ~loc
+                {|%%%%private extension expects a definition as its argument. Example: %%%%private(let a = "Hello")|};
             aux
               (Ext_list.rev_map_append work acc (fun x ->
                    self.structure_item self x))