diff --git a/dist/index.js b/dist/index.js
index 1bda23f..4284a52 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -1369,25 +1369,36 @@ class GitHubHelper {
             let treeSha = parentCommit.tree;
             if (commit.changes.length > 0) {
                 core.info(`Creating tree objects for local commit ${commit.sha}`);
-                const treeObjects = yield Promise.all(commit.changes.map((_a) => __awaiter(this, [_a], void 0, function* ({ path, mode, status }) {
-                    let sha = null;
-                    if (status === 'A' || status === 'M') {
-                        try {
-                            const { data: blob } = yield blobCreationLimit(() => this.octokit.rest.git.createBlob(Object.assign(Object.assign({}, repository), { content: utils.readFileBase64([repoPath, path]), encoding: 'base64' })));
-                            sha = blob.sha;
-                        }
-                        catch (error) {
-                            core.error(`Error creating blob for file '${path}': ${utils.getErrorMessage(error)}`);
-                            throw error;
-                        }
+                const treeObjects = yield Promise.all(commit.changes.map((_a) => __awaiter(this, [_a], void 0, function* ({ path, mode, status, dstSha }) {
+                    if (mode === '160000') {
+                        // submodule
+                        return {
+                            path,
+                            mode,
+                            sha: dstSha,
+                            type: 'commit'
+                        };
+                    }
+                    else {
+                        let sha = null;
+                        if (status === 'A' || status === 'M') {
+                            try {
+                                const { data: blob } = yield blobCreationLimit(() => this.octokit.rest.git.createBlob(Object.assign(Object.assign({}, repository), { content: utils.readFileBase64([repoPath, path]), encoding: 'base64' })));
+                                sha = blob.sha;
+                                core.info(`Created blob for file '${path}'`);
+                            }
+                            catch (error) {
+                                core.error(`Error creating blob for file '${path}': ${utils.getErrorMessage(error)}`);
+                                throw error;
+                            }
+                        }
+                        return {
+                            path,
+                            mode,
+                            sha,
+                            type: 'blob'
+                        };
                     }
-                    core.info(`Created blob for file '${path}'`);
-                    return {
-                        path,
-                        mode,
-                        sha,
-                        type: 'blob'
-                    };
                 })));
                 const chunkSize = 100;
                 const chunkedTreeObjects = Array.from({ length: Math.ceil(treeObjects.length / chunkSize) }, (_, i) => treeObjects.slice(i * chunkSize, i * chunkSize + chunkSize));
diff --git a/src/github-helper.ts b/src/github-helper.ts
index ff549db..b34df59 100644
--- a/src/github-helper.ts
+++ b/src/github-helper.ts
@@ -35,7 +35,7 @@ type TreeObject = {
   path: string
   mode: '100644' | '100755' | '040000' | '160000' | '120000'
   sha: string | null
-  type: 'blob'
+  type: 'blob' | 'commit'
 }
 
 export class GitHubHelper {
@@ -255,31 +255,41 @@ export class GitHubHelper {
     if (commit.changes.length > 0) {
       core.info(`Creating tree objects for local commit ${commit.sha}`)
       const treeObjects = await Promise.all(
-        commit.changes.map(async ({path, mode, status}) => {
-          let sha: string | null = null
-          if (status === 'A' || status === 'M') {
-            try {
-              const {data: blob} = await blobCreationLimit(() =>
-                this.octokit.rest.git.createBlob({
-                  ...repository,
-                  content: utils.readFileBase64([repoPath, path]),
-                  encoding: 'base64'
-                })
-              )
-              sha = blob.sha
-            } catch (error) {
-              core.error(
-                `Error creating blob for file '${path}': ${utils.getErrorMessage(error)}`
-              )
-              throw error
+        commit.changes.map(async ({path, mode, status, dstSha}) => {
+          if (mode === '160000') {
+            // submodule
+            return <TreeObject>{
+              path,
+              mode,
+              sha: dstSha,
+              type: 'commit'
+            }
+          } else {
+            let sha: string | null = null
+            if (status === 'A' || status === 'M') {
+              try {
+                const {data: blob} = await blobCreationLimit(() =>
+                  this.octokit.rest.git.createBlob({
+                    ...repository,
+                    content: utils.readFileBase64([repoPath, path]),
+                    encoding: 'base64'
+                  })
+                )
+                sha = blob.sha
+                core.info(`Created blob for file '${path}'`)
+              } catch (error) {
+                core.error(
+                  `Error creating blob for file '${path}': ${utils.getErrorMessage(error)}`
+                )
+                throw error
+              }
+            }
+            return <TreeObject>{
+              path,
+              mode,
+              sha,
+              type: 'blob'
             }
-          }
-          core.info(`Created blob for file '${path}'`)
-          return <TreeObject>{
-            path,
-            mode,
-            sha,
-            type: 'blob'
           }
         })
       )