diff --git a/esphome/components/web_server/web_server.cpp b/esphome/components/web_server/web_server.cpp
index 80a53a7515..00b2e20015 100644
--- a/esphome/components/web_server/web_server.cpp
+++ b/esphome/components/web_server/web_server.cpp
@@ -428,6 +428,9 @@ void WebServer::on_switch_update(switch_::Switch *obj, bool state) {
 std::string WebServer::switch_json(switch_::Switch *obj, bool value, JsonDetail start_config) {
   return json::build_json([obj, value, start_config](JsonObject root) {
     set_json_icon_state_value(root, obj, "switch-" + obj->get_object_id(), value ? "ON" : "OFF", value, start_config);
+    if (start_config == DETAIL_ALL) {
+      root["assumed_state"] = obj->assumed_state();
+    }
   });
 }
 void WebServer::handle_switch_request(AsyncWebServerRequest *request, const UrlMatch &match) {