diff --git a/src/core/python2js.c b/src/core/python2js.c
index 7a12dc5f2..47cabfa51 100644
--- a/src/core/python2js.c
+++ b/src/core/python2js.c
@@ -86,7 +86,7 @@ int
 _python2js_remove_from_cache(PyObject* map, PyObject* pyparent);
 
 JsRef
-_python2js_cache(PyObject* x, PyObject* map);
+_python2js_cache(PyObject* x, PyObject* map, int depth);
 
 static JsRef
 _python2js_float(PyObject* x)
@@ -148,7 +148,7 @@ _python2js_bytes(PyObject* x)
 }
 
 static JsRef
-_python2js_sequence(PyObject* x, PyObject* map)
+_python2js_sequence(PyObject* x, PyObject* map, int depth)
 {
   JsRef jsarray = hiwire_array();
   if (_python2js_add_to_cache(map, x, jsarray)) {
@@ -167,7 +167,7 @@ _python2js_sequence(PyObject* x, PyObject* map)
       Py_INCREF(x);
       return pyproxy_new(x);
     }
-    JsRef jsitem = _python2js_cache(pyitem, map);
+    JsRef jsitem = _python2js_cache(pyitem, map, depth);
     if (jsitem == NULL) {
       _python2js_remove_from_cache(map, x);
       Py_DECREF(pyitem);
@@ -186,7 +186,7 @@ _python2js_sequence(PyObject* x, PyObject* map)
 }
 
 static JsRef
-_python2js_dict(PyObject* x, PyObject* map)
+_python2js_dict(PyObject* x, PyObject* map, int depth)
 {
   JsRef jsdict = hiwire_object();
   if (_python2js_add_to_cache(map, x, jsdict)) {
@@ -196,13 +196,13 @@ _python2js_dict(PyObject* x, PyObject* map)
   PyObject *pykey, *pyval;
   Py_ssize_t pos = 0;
   while (PyDict_Next(x, &pos, &pykey, &pyval)) {
-    JsRef jskey = _python2js_cache(pykey, map);
+    JsRef jskey = _python2js_cache(pykey, map, depth);
     if (jskey == NULL) {
       _python2js_remove_from_cache(map, x);
       hiwire_decref(jsdict);
       return NULL;
     }
-    JsRef jsval = _python2js_cache(pyval, map);
+    JsRef jsval = _python2js_cache(pyval, map, depth);
     if (jsval == NULL) {
       _python2js_remove_from_cache(map, x);
       hiwire_decref(jskey);
@@ -220,8 +220,17 @@ _python2js_dict(PyObject* x, PyObject* map)
   return jsdict;
 }
 
+#define RETURN_IF_SUCCEEDS(x)                                                  \
+  do {                                                                         \
+    JsRef _fresh_result = x;                                                   \
+    if (_fresh_result != NULL) {                                               \
+      return _fresh_result;                                                    \
+    }                                                                          \
+    PyErr_Clear();                                                             \
+  } while (0)
+
 static JsRef
-_python2js(PyObject* x, PyObject* map)
+_python2js_immutable(PyObject* x, PyObject* map, int depth)
 {
   if (x == Py_None) {
     return hiwire_undefined();
@@ -241,25 +250,38 @@ _python2js(PyObject* x, PyObject* map)
     return JsProxy_AsJs(x);
   } else if (JsException_Check(x)) {
     return JsException_AsJs(x);
-  } else if (PyList_Check(x) || PyTuple_Check(x)) {
-    return _python2js_sequence(x, map);
-  } else if (PyDict_Check(x)) {
-    return _python2js_dict(x, map);
-  } else {
-    JsRef ret = _python2js_buffer(x);
+  } else if (PyTuple_Check(x)) {
+    return _python2js_sequence(x, map, depth);
+  }
+  return NULL;
+}
 
-    if (ret != NULL) {
-      return ret;
-    }
-    PyErr_Clear();
-    if (PySequence_Check(x)) {
-      return _python2js_sequence(x, map);
-    }
+static JsRef
+_python2js_deep(PyObject* x, PyObject* map, int depth)
+{
+  RETURN_IF_SUCCEEDS(_python2js_immutable(x, map, depth));
+  if (PyList_Check(x)) {
+    return _python2js_sequence(x, map, depth);
+  }
+  if (PyDict_Check(x)) {
+    return _python2js_dict(x, map, depth);
+  }
+  RETURN_IF_SUCCEEDS(_python2js_buffer(x));
 
-    // Proxies we've already created are just returned again, so that the
-    // same object on the Python side is always the same object on the
-    // Javascript side.
+  if (PySequence_Check(x)) {
+    return _python2js_sequence(x, map, depth);
+  }
+  return pyproxy_new(x);
+}
+
+static JsRef
+_python2js(PyObject* x, PyObject* map, int depth)
+{
+  if (depth == 0) {
+    RETURN_IF_SUCCEEDS(_python2js_immutable(x, map, 0));
     return pyproxy_new(x);
+  } else {
+    return _python2js_deep(x, map, depth - 1);
   }
 }
 
@@ -299,7 +321,7 @@ _python2js_remove_from_cache(PyObject* map, PyObject* pyparent)
 }
 
 JsRef
-_python2js_cache(PyObject* x, PyObject* map)
+_python2js_cache(PyObject* x, PyObject* map, int depth)
 {
   PyObject* id = PyLong_FromSize_t((size_t)x);
   PyObject* val = PyDict_GetItem(map, id);
@@ -310,7 +332,7 @@ _python2js_cache(PyObject* x, PyObject* map)
       result = hiwire_incref(result);
     }
   } else {
-    result = _python2js(x, map);
+    result = _python2js(x, map, depth);
   }
   Py_DECREF(id);
   return result;
@@ -320,7 +342,7 @@ JsRef
 python2js(PyObject* x)
 {
   PyObject* map = PyDict_New();
-  JsRef result = _python2js_cache(x, map);
+  JsRef result = _python2js_cache(x, map, -1);
   Py_DECREF(map);
 
   if (result == NULL) {
@@ -330,10 +352,63 @@ python2js(PyObject* x)
   return result;
 }
 
+JsRef
+python2js_with_depth(PyObject* x, int depth)
+{
+  PyObject* map = PyDict_New();
+  JsRef result = _python2js_cache(x, map, depth);
+  Py_DECREF(map);
+
+  if (result == NULL) {
+    pythonexc2js();
+  }
+
+  return result;
+}
+
+PyObject* globals;
+
+JsRef
+test_python2js_with_depth(char* name, int depth)
+{
+  PyObject* pyname = PyUnicode_FromString(name);
+  PyObject* pyval = PyDict_GetItem(globals, pyname);
+  if (pyval == NULL) {
+    if (!PyErr_Occurred()) {
+      PyErr_Format(PyExc_KeyError, "%s", name);
+    }
+    Py_DECREF(pyname);
+    pythonexc2js();
+    return NULL;
+  }
+
+  Py_DECREF(pyname);
+  JsRef idval = python2js_with_depth(pyval, depth);
+  return idval;
+}
+
 int
 python2js_init()
 {
   bool success = false;
+  PyObject* __main__ = PyImport_AddModule("__main__"); // borrowed!
+  FAIL_IF_NULL(__main__);
+
+  globals = PyModule_GetDict(__main__);
+  FAIL_IF_NULL(globals);
+
+  EM_ASM({
+    Module.test_python2js_with_depth = function(name, depth)
+    {
+      let pyname = stringToNewUTF8(name);
+      let idresult = _test_python2js_with_depth(pyname, depth);
+      jsresult = Module.hiwire.get_value(idresult);
+      Module.hiwire.decref(idresult);
+      _free(pyname);
+      return jsresult;
+    };
+  });
+
   tbmod = PyImport_ImportModule("traceback");
   FAIL_IF_NULL(tbmod);
   success = true;
diff --git a/src/tests/test_typeconversions.py b/src/tests/test_typeconversions.py
index 0aa22a01c..d475c9749 100644
--- a/src/tests/test_typeconversions.py
+++ b/src/tests/test_typeconversions.py
@@ -352,3 +352,85 @@ def test_memoryview_conversion(selenium):
         // (automatically checked in conftest.py)
         """
     )
+
+
+def test_python2js_with_depth(selenium):
+
+    selenium.run("a = [1, 2, 3]")
+    assert selenium.run_js(
+        """
+        res = pyodide._module.test_python2js_with_depth("a", -1);
+        return (Array.isArray(res)) && JSON.stringify(res) === "[1,2,3]";
+        """
+    )
+
+    selenium.run("a = (1, 2, 3)")
+    assert selenium.run_js(
+        """
+        res = pyodide._module.test_python2js_with_depth("a", -1);
+        return (Array.isArray(res)) && JSON.stringify(res) === "[1,2,3]";
+        """
+    )
+
+    selenium.run("a = [(1,2), (3,4), [5, 6], { 2 : 3,  4 : 9}]")
+    assert selenium.run_js(
+        """
+        res = pyodide._module.test_python2js_with_depth("a", -1);
+        return Array.isArray(res) && \
+            JSON.stringify(res) === `[[1,2],[3,4],[5,6],{"2":3,"4":9}]`;
+        """
+    )
+
+    selenium.run(
+        """
+        a = [1,[2,[3,[4,[5,[6,[7]]]]]]]
+        """
+    )
+    selenium.run_js(
+        """
+        function assert(x, msg){
+            if(x !== true){
+                throw new Error(`Assertion failed: ${msg}`);
+            }
+        }
+        for(let i=0; i < 7; i++){
+            let x = pyodide._module.test_python2js_with_depth("a", i);
+            for(let j=0; j < i; j++){
+                assert(Array.isArray(x), `i: ${i}, j: ${j}`);
+                x = x[1];
+            }
+            assert(pyodide._module.PyProxy.isPyProxy(x), `i: ${i}, j: ${i}`);
+        }
+        """
+    )
+
+    selenium.run("a = [1, (2, (3, [4, (5, (6, [7]))]))]")
+    selenium.run_js(
+        """
+        function assert(x, msg){
+            if(x !== true){
+                throw new Error(`Assertion failed: ${msg}`);
+            }
+        }
+        let depths = [0, 3, 3, 3, 6, 6, 6]
+        for(let i=0; i < 7; i++){
+            let x = pyodide._module.test_python2js_with_depth("a", i);
+            for(let j=0; j < depths[i]; j++){
+                assert(Array.isArray(x), `i: ${i}, j: ${j}`);
+                x = x[1];
+            }
+            assert(pyodide._module.PyProxy.isPyProxy(x), `i: ${i}, j: ${i}`);
+        }
+        """
+    )
+
+
+@pytest.mark.xfail
+def test_py2js_set(selenium):
+    selenium.run("a = {1, 2, 3}")
+    assert selenium.run_js(
+        """
+        let res = pyodide._module.test_python2js_with_depth("a", -1);
+        return res instanceof Set;
+        """
+    )