diff --git a/src/build.ts b/src/build.ts
index 94aa026..6aae9c7 100644
--- a/src/build.ts
+++ b/src/build.ts
@@ -9,7 +9,13 @@ import { defu } from "defu";
 import { createHooks } from "hookable";
 import prettyBytes from "pretty-bytes";
 import { glob } from "tinyglobby";
-import { dumpObject, rmdir, resolvePreset, removeExtension } from "./utils";
+import {
+  dumpObject,
+  rmdir,
+  resolvePreset,
+  removeExtension,
+  inferPkgExternals,
+} from "./utils";
 import type { BuildContext, BuildConfig, BuildOptions } from "./types";
 import { validatePackage, validateDependencies } from "./validate";
 import { rollupBuild } from "./builders/rollup";
@@ -228,7 +234,8 @@ async function _build(
   options.devDependencies = Object.keys(pkg.devDependencies || {});
 
   // Add all dependencies as externals
-  options.externals.push(...options.dependencies, ...options.peerDependencies);
+  options.externals.push(...inferPkgExternals(pkg));
+  options.externals = [...new Set(options.externals)];
 
   // Call build:before
   await ctx.hooks.callHook("build:before", ctx);
diff --git a/src/utils.ts b/src/utils.ts
index 7dee9bb..b2f1702 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -162,3 +162,42 @@ export function arrayIncludes(
 export function removeExtension(filename: string): string {
   return filename.replace(/\.(js|mjs|cjs|ts|mts|cts|json|jsx|tsx)$/, "");
 }
+
+export function inferPkgExternals(pkg: PackageJson): (string | RegExp)[] {
+  const externals: (string | RegExp)[] = [
+    ...Object.keys(pkg.dependencies || {}),
+    ...Object.keys(pkg.peerDependencies || {}),
+    ...Object.keys(pkg.devDependencies || {}),
+    ...Object.keys(pkg.optionalDependencies || {}),
+  ];
+
+  if (pkg.name) {
+    externals.push(pkg.name);
+    if (pkg.exports) {
+      for (const subpath of Object.keys(pkg.exports)) {
+        if (subpath.startsWith("./")) {
+          externals.push(pathToRegex(`${pkg.name}/${subpath.slice(2)}`));
+        }
+      }
+    }
+  }
+
+  if (pkg.imports) {
+    for (const importName of Object.keys(pkg.imports)) {
+      if (importName.startsWith("#")) {
+        externals.push(pathToRegex(importName));
+      }
+    }
+  }
+
+  return [...new Set(externals)];
+}
+
+function pathToRegex(path: string): string | RegExp {
+  if (!path.includes("*")) {
+    return path;
+  }
+  return new RegExp(
+    path.replace(/\./g, String.raw`\.`).replace(/\*/g, ".*") + "$",
+  );
+}
diff --git a/test/utils.test.ts b/test/utils.test.ts
index d308381..2f38684 100644
--- a/test/utils.test.ts
+++ b/test/utils.test.ts
@@ -3,6 +3,7 @@ import {
   arrayIncludes,
   extractExportFilenames,
   inferExportType,
+  inferPkgExternals,
 } from "../src/utils";
 
 describe("inferExportType", () => {
@@ -52,3 +53,38 @@ describe("arrayIncludes", () => {
     expect(arrayIncludes([/t3$/, "test2"], "test1")).to.eq(false);
   });
 });
+
+describe("inferPkgExternals", () => {
+  it("infers externals from package.json", () => {
+    expect(
+      inferPkgExternals({
+        name: "test",
+        dependencies: { react: "17.0.0" },
+        peerDependencies: { "react-dom": "17.0.0" },
+        devDependencies: { "@types/react": "17.0.0" },
+        optionalDependencies: { test: "1.0.0", optional: "1.0.0" },
+        exports: {
+          ".": "index.js",
+          "./extra/utils": "utils.js",
+          "./drivers/*.js": "drivers/*.js",
+          invalid: "invalid.js",
+        },
+        imports: {
+          "#*": "src/*",
+          "#test": "test.js",
+          invalid: "invalid.js",
+        },
+      }),
+    ).to.deep.equal([
+      "react",
+      "react-dom",
+      "@types/react",
+      "test",
+      "optional",
+      "test/extra/utils",
+      /test\/drivers\/.*\.js$/,
+      /#.*$/,
+      "#test",
+    ]);
+  });
+});