diff --git a/v2/lib/commands/start.js b/v2/lib/commands/start.js
index 581eee8445..b21700ea1b 100644
--- a/v2/lib/commands/start.js
+++ b/v2/lib/commands/start.js
@@ -40,7 +40,12 @@ module.exports = async function start(siteDir, cliOptions = {}) {
     };
     const docsRelativeDir = props.siteConfig.customDocsPath;
     const fsWatcher = chokidar.watch(
-      [`../${docsRelativeDir}/**/*.md`, 'blog/**/*.md', 'siteConfig.js'],
+      [
+        `../${docsRelativeDir}/**/*.md`,
+        'blog/**/*.md',
+        'siteConfig.js',
+        'sidebars.json',
+      ],
       {
         cwd: siteDir,
         ignoreInitial: true,
diff --git a/v2/lib/load/docs/sidebars.js b/v2/lib/load/docs/sidebars.js
index ac901ab195..0d8a97b024 100644
--- a/v2/lib/load/docs/sidebars.js
+++ b/v2/lib/load/docs/sidebars.js
@@ -2,11 +2,14 @@ const fs = require('fs-extra');
 const path = require('path');
 const {idx} = require('../utils');
 
-module.exports = function loadSidebars({siteDir, env}) {
+module.exports = function loadSidebars({siteDir, env}, deleteCache = true) {
   let allSidebars = {};
 
   // current sidebars
   const sidebarsJSONFile = path.join(siteDir, 'sidebars.json');
+  if (deleteCache) {
+    delete require.cache[sidebarsJSONFile];
+  }
   if (fs.existsSync(sidebarsJSONFile)) {
     allSidebars = require(sidebarsJSONFile); // eslint-disable-line
   }