diff --git a/.changeset/beige-years-notice.md b/.changeset/beige-years-notice.md
new file mode 100644
index 00000000000..a26a6c97230
--- /dev/null
+++ b/.changeset/beige-years-notice.md
@@ -0,0 +1,5 @@
+---
+'@primer/components': patch
+---
+
+Side effects are properly declared in package.json
diff --git a/package-lock.json b/package-lock.json
index 2a904e3cfc8..964270abcaf 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "@primer/components",
-  "version": "28.2.3",
+  "version": "28.2.5",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 6aa720e72bf..6d740777243 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,10 @@
   "main": "lib/index.js",
   "module": "lib-esm/index.js",
   "typings": "lib/index.d.ts",
+  "sideEffects": [
+    "(lib|lib-esm)/behaviors/focusZone.js",
+    "(lib|lib-esm)/behaviors/focusTrap.js"
+  ],
   "scripts": {
     "start": "cd docs && npm run develop",
     "predist": "rm -rf dist & rm -rf lib & rm -rf lib-esm",