diff --git a/.changeset/flat-starfishes-melt.md b/.changeset/flat-starfishes-melt.md
new file mode 100644
index 0000000..05b4484
--- /dev/null
+++ b/.changeset/flat-starfishes-melt.md
@@ -0,0 +1,5 @@
+---
+"@tksst/next-app-additions": minor
+---
+
+Set ECMAScript version in tsconfig.json to ESNEXT. (Browser compatibility is handled by webpack)
diff --git a/src/bin/index.ts b/src/bin/index.ts
index 499f6bc..30f0824 100644
--- a/src/bin/index.ts
+++ b/src/bin/index.ts
@@ -133,7 +133,7 @@ const main = async (): Promise<void> => {
             throw new Error("tsconfig.json is in an unexpected format.");
         }
 
-        x.target = "ES2015";
+        x.target = "esnext";
         x.noImplicitOverride = true;
         x.noImplicitReturns = true;
         x.noUncheckedIndexedAccess = true;