diff --git a/dist/index.js b/dist/index.js
index 4ade91c..36c0105 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -9583,14 +9583,25 @@ function getDefaultBranch(authToken, owner, repo) {
         return yield retryHelper.execute(() => __awaiter(this, void 0, void 0, function* () {
             core.info('Retrieving the default branch name');
             const octokit = new github.GitHub(authToken);
-            const response = yield octokit.repos.get({ owner, repo });
-            if (response.status != 200) {
-                throw new Error(`Unexpected response from GitHub API. Status: ${response.status}, Data: ${response.data}`);
+            let result;
+            try {
+                // Get the default branch from the repo info
+                const response = yield octokit.repos.get({ owner, repo });
+                result = response.data.default_branch;
+                assert.ok(result, 'default_branch cannot be empty');
+            }
+            catch (err) {
+                // Handle .wiki repo
+                if (err['status'] === 404 && repo.toUpperCase().endsWith('.WIKI')) {
+                    result = 'master';
+                }
+                // Otherwise error
+                else {
+                    throw err;
+                }
             }
             // Print the default branch
-            let result = response.data.default_branch;
             core.info(`Default branch '${result}'`);
-            assert.ok(result, 'default_branch cannot be empty');
             // Prefix with 'refs/heads'
             if (!result.startsWith('refs/')) {
                 result = `refs/heads/${result}`;
diff --git a/src/github-api-helper.ts b/src/github-api-helper.ts
index 7a09638..15ac77e 100644
--- a/src/github-api-helper.ts
+++ b/src/github-api-helper.ts
@@ -8,6 +8,7 @@ import * as retryHelper from './retry-helper'
 import * as toolCache from '@actions/tool-cache'
 import {default as uuid} from 'uuid/v4'
 import {Octokit} from '@octokit/rest'
+import {Console} from 'console'
 
 const IS_WINDOWS = process.platform === 'win32'
 
@@ -78,17 +79,25 @@ export async function getDefaultBranch(
   return await retryHelper.execute(async () => {
     core.info('Retrieving the default branch name')
     const octokit = new github.GitHub(authToken)
-    const response = await octokit.repos.get({owner, repo})
-    if (response.status != 200) {
-      throw new Error(
-        `Unexpected response from GitHub API. Status: ${response.status}, Data: ${response.data}`
-      )
+    let result: string
+    try {
+      // Get the default branch from the repo info
+      const response = await octokit.repos.get({owner, repo})
+      result = response.data.default_branch
+      assert.ok(result, 'default_branch cannot be empty')
+    } catch (err) {
+      // Handle .wiki repo
+      if (err['status'] === 404 && repo.toUpperCase().endsWith('.WIKI')) {
+        result = 'master'
+      }
+      // Otherwise error
+      else {
+        throw err
+      }
     }
 
     // Print the default branch
-    let result = response.data.default_branch
     core.info(`Default branch '${result}'`)
-    assert.ok(result, 'default_branch cannot be empty')
 
     // Prefix with 'refs/heads'
     if (!result.startsWith('refs/')) {