diff --git a/py/builtinimport.c b/py/builtinimport.c
index ffdadf0227..1272d59413 100644
--- a/py/builtinimport.c
+++ b/py/builtinimport.c
@@ -44,6 +44,7 @@
 #include "runtime0.h"
 #include "runtime.h"
 #include "builtin.h"
+#include "builtintables.h"
 
 #if 0 // print debugging info
 #define DEBUG_PRINT (1)
@@ -251,12 +252,29 @@ mp_obj_t mp_builtin___import__(mp_uint_t n_args, mp_obj_t *args) {
             }
             DEBUG_printf("Current path: %s\n", vstr_str(&path));
 
-            // fail if we couldn't find the file
             if (stat == MP_IMPORT_STAT_NO_EXIST) {
-                nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ImportError, "No module named '%s'", qstr_str(mod_name)));
+                #if MICROPY_MODULE_WEAK_LINKS
+                // check if there is a weak link to this module
+                if (i == mod_len) {
+                    mp_map_elem_t *el = mp_map_lookup((mp_map_t*)&mp_builtin_module_weak_links_dict_obj.map, MP_OBJ_NEW_QSTR(mod_name), MP_MAP_LOOKUP);
+                    if (el == NULL) {
+                        goto no_exist;
+                    }
+                    // found weak linked module
+                    module_obj = el->value;
+                } else {
+                    no_exist:
+                #else
+                {
+                #endif
+                    // couldn't find the file, so fail
+                    nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ImportError, "No module named '%s'", qstr_str(mod_name)));
+                }
+            } else {
+                // found the file, so get the module
+                module_obj = mp_module_get(mod_name);
             }
 
-            module_obj = mp_module_get(mod_name);
             if (module_obj == MP_OBJ_NULL) {
                 // module not already loaded, so load it!
 
diff --git a/py/builtintables.c b/py/builtintables.c
index 1fd60d8177..6d74961384 100644
--- a/py/builtintables.c
+++ b/py/builtintables.c
@@ -227,3 +227,20 @@ const mp_obj_dict_t mp_builtin_module_dict_obj = {
         .table = (mp_map_elem_t*)mp_builtin_module_table,
     },
 };
+
+#if MICROPY_MODULE_WEAK_LINKS
+STATIC const mp_map_elem_t mp_builtin_module_weak_links_table[] = {
+    MICROPY_PORT_BUILTIN_MODULE_WEAK_LINKS
+};
+
+const mp_obj_dict_t mp_builtin_module_weak_links_dict_obj = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = MP_ARRAY_SIZE(mp_builtin_module_weak_links_table),
+        .alloc = MP_ARRAY_SIZE(mp_builtin_module_weak_links_table),
+        .table = (mp_map_elem_t*)mp_builtin_module_weak_links_table,
+    },
+};
+#endif
diff --git a/py/builtintables.h b/py/builtintables.h
index 96fc813aba..5a865a78b4 100644
--- a/py/builtintables.h
+++ b/py/builtintables.h
@@ -26,3 +26,7 @@
 
 extern const mp_obj_dict_t mp_builtin_object_dict_obj;
 extern const mp_obj_dict_t mp_builtin_module_dict_obj;
+
+#if MICROPY_MODULE_WEAK_LINKS
+extern const mp_obj_dict_t mp_builtin_module_weak_links_dict_obj;
+#endif
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 92b61d0e12..13ccb9ca98 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -269,6 +269,11 @@ typedef double mp_float_t;
 #define MICROPY_STREAMS_NON_BLOCK (0)
 #endif
 
+// Whether module weak links are supported
+#ifndef MICROPY_MODULE_WEAK_LINKS
+#define MICROPY_MODULE_WEAK_LINKS (0)
+#endif
+
 /*****************************************************************************/
 /* Fine control over Python builtins, classes, modules, etc                  */
 
@@ -411,6 +416,11 @@ typedef double mp_float_t;
 #define MICROPY_PORT_BUILTIN_MODULES
 #endif
 
+// Any module weak links - see builtintables.c:mp_builtin_module_weak_links_table.
+#ifndef MICROPY_PORT_BUILTIN_MODULE_WEAK_LINKS
+#define MICROPY_PORT_BUILTIN_MODULE_WEAK_LINKS
+#endif
+
 // Additional constant definitions for the compiler - see compile.c:mp_constants_table.
 #ifndef MICROPY_PORT_CONSTANTS
 #define MICROPY_PORT_CONSTANTS