diff --git a/packages/docusaurus/src/server/__tests__/configValidation.test.ts b/packages/docusaurus/src/server/__tests__/configValidation.test.ts
index 008f71c71588..70eaa3900e3c 100644
--- a/packages/docusaurus/src/server/__tests__/configValidation.test.ts
+++ b/packages/docusaurus/src/server/__tests__/configValidation.test.ts
@@ -37,6 +37,7 @@ describe('normalizeConfig', () => {
       organizationName: 'facebook',
       projectName: 'docusaurus',
       githubHost: 'github.com',
+      githubPort: '8000',
       customFields: {
         myCustomField: '42',
       },
diff --git a/packages/docusaurus/src/server/configValidation.ts b/packages/docusaurus/src/server/configValidation.ts
index a76b56cc2be6..f8a0985903a8 100644
--- a/packages/docusaurus/src/server/configValidation.ts
+++ b/packages/docusaurus/src/server/configValidation.ts
@@ -185,6 +185,7 @@ export const ConfigSchema = Joi.object({
   deploymentBranch: Joi.string().optional(),
   customFields: Joi.object().unknown().default(DEFAULT_CONFIG.customFields),
   githubHost: Joi.string(),
+  githubPort: Joi.string(),
   plugins: Joi.array().items(PluginSchema).default(DEFAULT_CONFIG.plugins),
   themes: Joi.array().items(ThemeSchema).default(DEFAULT_CONFIG.themes),
   presets: Joi.array().items(PresetSchema).default(DEFAULT_CONFIG.presets),