diff --git a/src/globals.h b/src/globals.h
index f04b29e..94da8e0 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1643,6 +1643,7 @@
 EXTERN int  ui_delay_for_testing INIT(= 0);
 EXTERN int  reset_term_props_on_termresponse INIT(= FALSE);
 EXTERN long override_sysinfo_uptime INIT(= -1);
+EXTERN int  override_autoload INIT(= FALSE);
 
 EXTERN int  in_free_unref_items INIT(= FALSE);
 #endif
diff --git a/src/testdir/test_vim9_import.vim b/src/testdir/test_vim9_import.vim
index 553ef8f..2e57fe2 100644
--- a/src/testdir/test_vim9_import.vim
+++ b/src/testdir/test_vim9_import.vim
@@ -1288,6 +1288,42 @@
   &rtp = save_rtp
 enddef
 
+def Test_import_autoload_override()
+  mkdir('Xdir/autoload', 'p')
+  var save_rtp = &rtp
+  exe 'set rtp^=' .. getcwd() .. '/Xdir'
+  test_override('autoload', 1)
+
+  var lines =<< trim END
+      vim9script autoload
+
+      g:loaded_override = 'true'
+      export var variable = 'bla'
+      export def Function(): string
+        return 'bla'
+      enddef
+  END
+  writefile(lines, 'Xdir/autoload/override.vim')
+
+  lines =<< trim END
+      vim9script
+
+      import autoload 'override.vim'
+      assert_equal('true', g:loaded_override)
+
+      def Tryit()
+        echo override.doesNotExist
+      enddef
+      defcompile
+  END
+  CheckScriptFailure(lines, 'E1048: Item not found in script: doesNotExist', 1)
+
+  test_override('autoload', 0)
+  unlet g:loaded_override
+  delete('Xdir', 'rf')
+  &rtp = save_rtp
+enddef
+
 def Test_autoload_mapping()
   mkdir('Xdir/autoload', 'p')
   var save_rtp = &rtp
diff --git a/src/testing.c b/src/testing.c
index eef5e0d..3482682 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -1055,6 +1055,8 @@
 	    reset_term_props_on_termresponse = val;
 	else if (STRCMP(name, (char_u *)"uptime") == 0)
 	    override_sysinfo_uptime = val;
+	else if (STRCMP(name, (char_u *)"autoload") == 0)
+	    override_autoload = val;
 	else if (STRCMP(name, (char_u *)"ALL") == 0)
 	{
 	    disable_char_avail_for_testing = FALSE;
diff --git a/src/version.c b/src/version.c
index 728d2b8..782a64a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4087,
+/**/
     4086,
 /**/
     4085,
diff --git a/src/vim9script.c b/src/vim9script.c
index baf2019..2038c78 100644
--- a/src/vim9script.c
+++ b/src/vim9script.c
@@ -496,6 +496,9 @@
 	    if (si->sn_autoload_prefix == NULL)
 		si->sn_autoload_prefix = get_autoload_prefix(si);
 	    res = OK;
+	    if (override_autoload && si->sn_state == SN_STATE_NOT_LOADED)
+		// testing override: load autoload script right away
+		(void)do_source(si->sn_name, FALSE, DOSO_NONE, NULL);
 	}
 	else
 	    res = FAIL;