diff --git a/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.js b/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.js
index c19045bf15..06eea9f19a 100644
--- a/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.js
+++ b/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.js
@@ -93,6 +93,22 @@ describe('themeConfig', () => {
     });
   });
 
+  test('should allow empty alt tags for the logo image in the header', () => {
+    const altTagConfig = {
+      navbar: {
+        logo: {
+          alt: '',
+          src: '/arbitrary-logo.png',
+        },
+        hideOnScroll: false,
+      },
+    };
+    expect(testValidateThemeConfig(altTagConfig)).toEqual({
+      colorMode: DEFAULT_COLOR_MODE_CONFIG,
+      ...altTagConfig,
+    });
+  });
+
   test('should accept valid prism config', () => {
     const prismConfig = {
       prism: {
diff --git a/packages/docusaurus-theme-classic/src/validateThemeConfig.js b/packages/docusaurus-theme-classic/src/validateThemeConfig.js
index 279ea29f00..7290fcdda2 100644
--- a/packages/docusaurus-theme-classic/src/validateThemeConfig.js
+++ b/packages/docusaurus-theme-classic/src/validateThemeConfig.js
@@ -181,7 +181,7 @@ const ThemeConfigSchema = Joi.object({
     items: Joi.array().items(NavbarItemSchema),
     title: Joi.string().allow('', null),
     logo: Joi.object({
-      alt: Joi.string(),
+      alt: Joi.string().allow(''),
       src: Joi.string().required(),
       srcDark: Joi.string(),
       href: Joi.string(),