diff --git a/Include/internal/pycore_dict.h b/Include/internal/pycore_dict.h
index b4e1f8cf1e320b..ff74ae9b61d1cd 100644
--- a/Include/internal/pycore_dict.h
+++ b/Include/internal/pycore_dict.h
@@ -22,6 +22,9 @@ extern int _PyDict_DelItemIf(PyObject *mp, PyObject *key,
 // Export for '_asyncio' shared extension
 PyAPI_FUNC(int) _PyDict_SetItem_KnownHash(PyObject *mp, PyObject *key,
                                           PyObject *item, Py_hash_t hash);
+int _PyDict_SetItem_KnownHash_LockHeld(PyObject *mp, PyObject *key,
+                                       PyObject *item, Py_hash_t hash);
+
 // Export for '_asyncio' shared extension
 PyAPI_FUNC(int) _PyDict_DelItem_KnownHash(PyObject *mp, PyObject *key,
                                           Py_hash_t hash);
diff --git a/Objects/clinic/odictobject.c.h b/Objects/clinic/odictobject.c.h
index 5ef5380656905a..de38d8a7af9200 100644
--- a/Objects/clinic/odictobject.c.h
+++ b/Objects/clinic/odictobject.c.h
@@ -6,6 +6,7 @@ preserve
 #  include "pycore_gc.h"          // PyGC_Head
 #  include "pycore_runtime.h"     // _Py_ID()
 #endif
+#include "pycore_critical_section.h"// Py_BEGIN_CRITICAL_SECTION()
 #include "pycore_modsupport.h"    // _PyArg_UnpackKeywords()
 
 PyDoc_STRVAR(OrderedDict_fromkeys__doc__,
@@ -129,7 +130,9 @@ OrderedDict_setdefault(PyODictObject *self, PyObject *const *args, Py_ssize_t na
     }
     default_value = args[1];
 skip_optional_pos:
+    Py_BEGIN_CRITICAL_SECTION(self);
     return_value = OrderedDict_setdefault_impl(self, key, default_value);
+    Py_END_CRITICAL_SECTION();
 
 exit:
     return return_value;
@@ -195,7 +198,9 @@ OrderedDict_pop(PyODictObject *self, PyObject *const *args, Py_ssize_t nargs, Py
     }
     default_value = args[1];
 skip_optional_pos:
+    Py_BEGIN_CRITICAL_SECTION(self);
     return_value = OrderedDict_pop_impl(self, key, default_value);
+    Py_END_CRITICAL_SECTION();
 
 exit:
     return return_value;
@@ -260,7 +265,9 @@ OrderedDict_popitem(PyODictObject *self, PyObject *const *args, Py_ssize_t nargs
         goto exit;
     }
 skip_optional_pos:
+    Py_BEGIN_CRITICAL_SECTION(self);
     return_value = OrderedDict_popitem_impl(self, last);
+    Py_END_CRITICAL_SECTION();
 
 exit:
     return return_value;
@@ -327,9 +334,11 @@ OrderedDict_move_to_end(PyODictObject *self, PyObject *const *args, Py_ssize_t n
         goto exit;
     }
 skip_optional_pos:
+    Py_BEGIN_CRITICAL_SECTION(self);
     return_value = OrderedDict_move_to_end_impl(self, key, last);
+    Py_END_CRITICAL_SECTION();
 
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=eff78d2a3f9379bd input=a9049054013a1b77]*/
+/*[clinic end generated code: output=78be92f03a70dee4 input=a9049054013a1b77]*/
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 23d7e9b5e38a35..731e9446f6661f 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -113,17 +113,18 @@ As a consequence of this, split keys have a maximum size of 16.
 #define PyDict_MINSIZE 8
 
 #include "Python.h"
-#include "pycore_bitutils.h"      // _Py_bit_length
-#include "pycore_call.h"          // _PyObject_CallNoArgs()
-#include "pycore_ceval.h"         // _PyEval_GetBuiltin()
-#include "pycore_code.h"          // stats
-#include "pycore_dict.h"          // export _PyDict_SizeOf()
-#include "pycore_gc.h"            // _PyObject_GC_IS_TRACKED()
-#include "pycore_object.h"        // _PyObject_GC_TRACK(), _PyDebugAllocatorStats()
-#include "pycore_pyerrors.h"      // _PyErr_GetRaisedException()
-#include "pycore_pystate.h"       // _PyThreadState_GET()
-#include "pycore_setobject.h"     // _PySet_NextEntry()
-#include "stringlib/eq.h"         // unicode_eq()
+#include "pycore_bitutils.h"            // _Py_bit_length
+#include "pycore_call.h"                // _PyObject_CallNoArgs()
+#include "pycore_ceval.h"               // _PyEval_GetBuiltin()
+#include "pycore_code.h"                // stats
+#include "pycore_critical_section.h"    // Py_BEGIN_CRITICAL_SECTION, Py_END_CRITICAL_SECTION
+#include "pycore_dict.h"                // export _PyDict_SizeOf()
+#include "pycore_gc.h"                  // _PyObject_GC_IS_TRACKED()
+#include "pycore_object.h"              // _PyObject_GC_TRACK(), _PyDebugAllocatorStats()
+#include "pycore_pyerrors.h"            // _PyErr_GetRaisedException()
+#include "pycore_pystate.h"             // _PyThreadState_GET()
+#include "pycore_setobject.h"           // _PySet_NextEntry()
+#include "stringlib/eq.h"               // unicode_eq()
 
 #include <stdbool.h>
 
@@ -1914,7 +1915,7 @@ PyDict_SetItem(PyObject *op, PyObject *key, PyObject *value)
 }
 
 int
-_PyDict_SetItem_KnownHash(PyObject *op, PyObject *key, PyObject *value,
+_PyDict_SetItem_KnownHash_LockHeld(PyObject *op, PyObject *key, PyObject *value,
                          Py_hash_t hash)
 {
     PyDictObject *mp;
@@ -1936,6 +1937,19 @@ _PyDict_SetItem_KnownHash(PyObject *op, PyObject *key, PyObject *value,
     return insertdict(interp, mp, Py_NewRef(key), hash, Py_NewRef(value));
 }
 
+int
+_PyDict_SetItem_KnownHash(PyObject *op, PyObject *key, PyObject *value,
+                         Py_hash_t hash)
+{
+    int res;
+
+    Py_BEGIN_CRITICAL_SECTION(op);
+    res = _PyDict_SetItem_KnownHash_LockHeld(op, key, value, hash);
+
+    Py_END_CRITICAL_SECTION();
+    return res;
+}
+
 static void
 delete_index_from_values(PyDictValues *values, Py_ssize_t ix)
 {
diff --git a/Objects/odictobject.c b/Objects/odictobject.c
index b5280c39e1be54..4d5f4e94ddf6cc 100644
--- a/Objects/odictobject.c
+++ b/Objects/odictobject.c
@@ -467,6 +467,7 @@ Potential Optimizations
 #include "Python.h"
 #include "pycore_call.h"          // _PyObject_CallNoArgs()
 #include "pycore_ceval.h"         // _PyEval_GetBuiltin()
+#include "pycore_critical_section.h"  // Py_BEGIN_CRITICAL_SECTION
 #include "pycore_dict.h"          // _Py_dict_lookup()
 #include "pycore_object.h"        // _PyObject_GC_UNTRACK()
 #include "pycore_pyerrors.h"      // _PyErr_ChainExceptions1()
@@ -984,6 +985,7 @@ odict_reduce(register PyODictObject *od, PyObject *Py_UNUSED(ignored))
 
 
 /*[clinic input]
+@critical_section
 OrderedDict.setdefault
 
     key: object
@@ -997,7 +999,7 @@ Return the value for key if key is in the dictionary, else default.
 static PyObject *
 OrderedDict_setdefault_impl(PyODictObject *self, PyObject *key,
                             PyObject *default_value)
-/*[clinic end generated code: output=97537cb7c28464b6 input=38e098381c1efbc6]*/
+/*[clinic end generated code: output=97537cb7c28464b6 input=d7b93e92734f99b5]*/
 {
     PyObject *result = NULL;
 
@@ -1069,6 +1071,7 @@ _odict_popkey_hash(PyObject *od, PyObject *key, PyObject *failobj,
 
 /* Skips __missing__() calls. */
 /*[clinic input]
+@critical_section
 OrderedDict.pop
 
     key: object
@@ -1083,7 +1086,7 @@ raise a KeyError.
 static PyObject *
 OrderedDict_pop_impl(PyODictObject *self, PyObject *key,
                      PyObject *default_value)
-/*[clinic end generated code: output=7a6447d104e7494b input=7efe36601007dff7]*/
+/*[clinic end generated code: output=7a6447d104e7494b input=a79988887b4a651f]*/
 {
     Py_hash_t hash = PyObject_Hash(key);
     if (hash == -1)
@@ -1095,6 +1098,7 @@ OrderedDict_pop_impl(PyODictObject *self, PyObject *key,
 /* popitem() */
 
 /*[clinic input]
+@critical_section
 OrderedDict.popitem
 
     last: bool = True
@@ -1106,7 +1110,7 @@ Pairs are returned in LIFO order if last is true or FIFO order if false.
 
 static PyObject *
 OrderedDict_popitem_impl(PyODictObject *self, int last)
-/*[clinic end generated code: output=98e7d986690d49eb input=d992ac5ee8305e1a]*/
+/*[clinic end generated code: output=98e7d986690d49eb input=8aafc7433e0a40e7]*/
 {
     PyObject *key, *value, *item = NULL;
     _ODictNode *node;
@@ -1251,6 +1255,7 @@ odict_reversed(PyODictObject *od, PyObject *Py_UNUSED(ignored))
 /* move_to_end() */
 
 /*[clinic input]
+@critical_section
 OrderedDict.move_to_end
 
     key: object
@@ -1263,7 +1268,7 @@ Raise KeyError if the element does not exist.
 
 static PyObject *
 OrderedDict_move_to_end_impl(PyODictObject *self, PyObject *key, int last)
-/*[clinic end generated code: output=fafa4c5cc9b92f20 input=d6ceff7132a2fcd7]*/
+/*[clinic end generated code: output=fafa4c5cc9b92f20 input=09f8bc7053c0f6d4]*/
 {
     _ODictNode *node;
 
@@ -1556,7 +1561,10 @@ static int
 _PyODict_SetItem_KnownHash(PyObject *od, PyObject *key, PyObject *value,
                            Py_hash_t hash)
 {
-    int res = _PyDict_SetItem_KnownHash(od, key, value, hash);
+    int res;
+    Py_BEGIN_CRITICAL_SECTION(od);
+
+    res = _PyDict_SetItem_KnownHash_LockHeld(od, key, value, hash);
     if (res == 0) {
         res = _odict_add_new_node((PyODictObject *)od, key, hash);
         if (res < 0) {
@@ -1566,11 +1574,13 @@ _PyODict_SetItem_KnownHash(PyObject *od, PyObject *key, PyObject *value,
             _PyErr_ChainExceptions1(exc);
         }
     }
+    Py_END_CRITICAL_SECTION();
     return res;
 }
 
-int
-PyODict_SetItem(PyObject *od, PyObject *key, PyObject *value)
+
+static int
+setitem_lock_held(PyObject *od, PyObject *key, PyObject *value)
 {
     Py_hash_t hash = PyObject_Hash(key);
     if (hash == -1)
@@ -1579,7 +1589,17 @@ PyODict_SetItem(PyObject *od, PyObject *key, PyObject *value)
 }
 
 int
-PyODict_DelItem(PyObject *od, PyObject *key)
+PyODict_SetItem(PyObject *od, PyObject *key, PyObject *value)
+{
+    int res;
+    Py_BEGIN_CRITICAL_SECTION(od);
+    res = setitem_lock_held(od, key, value);
+    Py_END_CRITICAL_SECTION();
+    return res;
+}
+
+static int
+del_item_lock_held(PyObject *od, PyObject *key)
 {
     int res;
     Py_hash_t hash = PyObject_Hash(key);
@@ -1591,6 +1611,16 @@ PyODict_DelItem(PyObject *od, PyObject *key)
     return _PyDict_DelItem_KnownHash(od, key, hash);
 }
 
+int
+PyODict_DelItem(PyObject *od, PyObject *key)
+{
+    int res;
+    Py_BEGIN_CRITICAL_SECTION(od);
+    res = del_item_lock_held(od, key);
+    Py_END_CRITICAL_SECTION();
+    return res;
+}
+
 
 /* -------------------------------------------
  * The OrderedDict views (keys/values/items)
@@ -1630,17 +1660,12 @@ odictiter_traverse(odictiterobject *di, visitproc visit, void *arg)
 /* In order to protect against modifications during iteration, we track
  * the current key instead of the current node. */
 static PyObject *
-odictiter_nextkey(odictiterobject *di)
+odictiter_nextkey_lock_held(odictiterobject *di)
 {
     PyObject *key = NULL;
     _ODictNode *node;
     int reversed = di->kind & _odict_ITER_REVERSED;
 
-    if (di->di_odict == NULL)
-        return NULL;
-    if (di->di_current == NULL)
-        goto done;  /* We're already done. */
-
     /* Check for unsupported changes. */
     if (di->di_odict->od_state != di->di_state) {
         PyErr_SetString(PyExc_RuntimeError,
@@ -1682,6 +1707,24 @@ odictiter_nextkey(odictiterobject *di)
     return key;
 }
 
+static PyObject *
+odictiter_nextkey(odictiterobject *di)
+{
+    if (di->di_odict == NULL)
+        return NULL;
+    if (di->di_current == NULL) {
+        Py_CLEAR(di->di_odict);
+        return NULL;
+    }
+
+
+    PyObject *res;
+    Py_BEGIN_CRITICAL_SECTION(di->di_odict);
+    res = odictiter_nextkey_lock_held(di);
+    Py_END_CRITICAL_SECTION();
+    return res;
+}
+
 static PyObject *
 odictiter_iternext(odictiterobject *di)
 {