diff --git a/dune-project b/dune-project
index a15d0426..082551c5 100644
--- a/dune-project
+++ b/dune-project
@@ -26,6 +26,7 @@
   ptime
   ambient-context
   (odoc :with-doc)
+  (alcotest :with-test)
   (pbrt
    (>= 2.3))
   (ocaml-lsp-server :with-dev-setup)
diff --git a/opentelemetry.opam b/opentelemetry.opam
index 168a88e6..d222450d 100644
--- a/opentelemetry.opam
+++ b/opentelemetry.opam
@@ -14,6 +14,7 @@ depends: [
   "ptime"
   "ambient-context"
   "odoc" {with-doc}
+  "alcotest" {with-test}
   "pbrt" {>= "2.3"}
   "ocaml-lsp-server" {with-dev-setup}
   "ocamlformat" {with-dev-setup & >= "0.24" & < "0.25"}
diff --git a/tests/implicit_scope/sync/dune b/tests/implicit_scope/sync/dune
new file mode 100644
index 00000000..072eee77
--- /dev/null
+++ b/tests/implicit_scope/sync/dune
@@ -0,0 +1,3 @@
+(tests
+ (names test_implicit_scope_sync)
+ (libraries alcotest opentelemetry opentelemetry-client-cohttp-lwt))
diff --git a/tests/implicit_scope/sync/test_implicit_scope_sync.ml b/tests/implicit_scope/sync/test_implicit_scope_sync.ml
new file mode 100644
index 00000000..d8bf632b
--- /dev/null
+++ b/tests/implicit_scope/sync/test_implicit_scope_sync.ml
@@ -0,0 +1,74 @@
+open Alcotest
+module Otel = Opentelemetry
+
+let spans_emitted : Otel.Proto.Trace.resource_spans list ref = ref []
+
+module Test_backend = struct
+  open Otel.Collector
+  open Otel.Proto
+  include Noop_backend
+
+  let record_emitted_spans (l : Trace.resource_spans list) ~ret =
+    spans_emitted := l @ !spans_emitted;
+    ret ()
+
+  let send_trace : Trace.resource_spans list sender =
+    { send = record_emitted_spans }
+end
+
+let with_test_backend f =
+  (* uncomment for eprintf debugging: *)
+  (* let module Debug_and_test_backend = Otel.Collector.Debug_backend (Test_backend) in
+     let backend = (module Debug_and_test_backend : Otel.Collector.BACKEND) in *)
+  let backend = (module Test_backend : Otel.Collector.BACKEND) in
+  Otel.Collector.with_setup_debug_backend backend () f
+
+let bytes_to_hex = Otel.Util_.bytes_to_hex
+
+let test_stack_based_implicit_scope () =
+  let run () =
+    Otel.Trace.with_ "first trace" @@ fun _scope ->
+    Thread.delay 0.2;
+    Otel.Trace.with_ "second trace" @@ fun _scope ->
+    Thread.delay 0.2;
+    Otel.Trace.with_ "third trace" @@ fun _scope ->
+    Thread.delay 0.2;
+    ()
+  in
+  with_test_backend @@ fun () ->
+  (* start *)
+  run ();
+  check' int ~msg:"count of spans emitted"
+    ~actual:(List.length !spans_emitted)
+    ~expected:3;
+  let open Otel.Proto.Trace in
+  let f prev_span_id { scope_spans; _ } =
+    Format.printf "\n%a@\n" (Format.pp_print_list pp_scope_spans) scope_spans;
+    check' int ~msg:"count of scope_spans in emitted span"
+      ~actual:(List.length scope_spans) ~expected:1;
+    let { scope; spans; _ } = List.hd scope_spans in
+    check' bool ~msg:"scope exists in emitted span"
+      ~actual:(Option.is_some scope) ~expected:true;
+    check' int ~msg:"count of spans in scope_span" ~actual:(List.length spans)
+      ~expected:1;
+    let { name; trace_id; span_id; parent_span_id; _ } = List.hd spans in
+    Printf.printf
+      "name='%s' trace_id='%s' span_id='%s' parent_span_id='%s' \
+       prev_span_id='%s'\n"
+      name (bytes_to_hex trace_id) (bytes_to_hex span_id)
+      (bytes_to_hex parent_span_id)
+      (bytes_to_hex prev_span_id);
+    check' string ~msg:"previous span is parent"
+      ~actual:(bytes_to_hex parent_span_id)
+      ~expected:(bytes_to_hex prev_span_id);
+    span_id
+  in
+  List.fold_left f (Bytes.of_string "") !spans_emitted |> ignore
+
+let suite =
+  [
+    test_case "stack-based implicit scope" `Quick
+      test_stack_based_implicit_scope;
+  ]
+
+let () = Alcotest.run "implicit scope" [ "sync", suite ]