diff --git a/modules/basic-theme/src/Volo.Abp.AspNetCore.Components.WebAssembly.BasicTheme/Themes/Basic/LanguageSwitch.razor b/modules/basic-theme/src/Volo.Abp.AspNetCore.Components.WebAssembly.BasicTheme/Themes/Basic/LanguageSwitch.razor
index bfc970c436..6f89696075 100644
--- a/modules/basic-theme/src/Volo.Abp.AspNetCore.Components.WebAssembly.BasicTheme/Themes/Basic/LanguageSwitch.razor
+++ b/modules/basic-theme/src/Volo.Abp.AspNetCore.Components.WebAssembly.BasicTheme/Themes/Basic/LanguageSwitch.razor
@@ -60,6 +60,11 @@
             "Abp.SelectedLanguage", language.UiCultureName
             );
 
+        await JsRuntime.InvokeVoidAsync(
+            "localStorage.setItem",
+            "Abp.IsRtl", CultureInfo.GetCultureInfo(language.UiCultureName).TextInfo.IsRightToLeft
+            );
+
         await JsRuntime.InvokeVoidAsync("location.reload");
     }
 }
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/wwwroot/index.html b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/wwwroot/index.html
index 5c5b4f161d..6fb36c2b23 100644
--- a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/wwwroot/index.html
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/wwwroot/index.html
@@ -26,5 +26,6 @@
     <script src="global.js?_v=637701705558615007"></script>
     <!--/ABP:Scripts-->
 
+    <script src="main.js"></script>
 </body>
 </html>
diff --git a/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/wwwroot/main.js b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/wwwroot/main.js
new file mode 100644
index 0000000000..a1f62022d8
--- /dev/null
+++ b/templates/app/aspnet-core/src/MyCompanyName.MyProjectName.Blazor/wwwroot/main.js
@@ -0,0 +1,17 @@
+(
+    function () {
+        var isRtl = JSON.parse(localStorage.getItem("Abp.IsRtl"));
+        var htmlTag = document.getElementsByTagName("html")[0];
+
+        if (htmlTag) {
+            var selectedLanguage = localStorage.getItem("Abp.SelectedLanguage");
+            if (selectedLanguage) {
+                htmlTag.setAttribute("lang", selectedLanguage);
+            }
+
+            if (isRtl) {
+                htmlTag.setAttribute("dir", "rtl");
+            }
+        }
+    }
+)();
\ No newline at end of file