diff --git a/packages/slate-history/package.json b/packages/slate-history/package.json
index 77d223638..1b808f472 100644
--- a/packages/slate-history/package.json
+++ b/packages/slate-history/package.json
@@ -9,6 +9,7 @@
   "types": "lib/index.d.ts",
   "umd": "dist/slate-history.js",
   "umdMin": "dist/slate-history.min.js",
+  "sideEffects": false,
   "files": [
     "dist/",
     "lib/"
diff --git a/packages/slate-hyperscript/package.json b/packages/slate-hyperscript/package.json
index f21f6dab8..0c013dd62 100644
--- a/packages/slate-hyperscript/package.json
+++ b/packages/slate-hyperscript/package.json
@@ -9,6 +9,7 @@
   "types": "lib/index.d.ts",
   "umd": "dist/slate-hyperscript.js",
   "umdMin": "dist/slate-hyperscript.min.js",
+  "sideEffects": false,
   "files": [
     "dist/",
     "lib/"
diff --git a/packages/slate-react/package.json b/packages/slate-react/package.json
index a23897f54..4082024bf 100644
--- a/packages/slate-react/package.json
+++ b/packages/slate-react/package.json
@@ -9,6 +9,7 @@
   "types": "lib/index.d.ts",
   "umd": "dist/slate-react.js",
   "umdMin": "dist/slate-react.min.js",
+  "sideEffects": false,
   "files": [
     "dist/",
     "lib/"
diff --git a/packages/slate-schema/package.json b/packages/slate-schema/package.json
index a31d92898..b2983013b 100644
--- a/packages/slate-schema/package.json
+++ b/packages/slate-schema/package.json
@@ -9,6 +9,7 @@
   "types": "lib/index.d.ts",
   "umd": "dist/slate-schema.js",
   "umdMin": "dist/slate-schema.min.js",
+  "sideEffects": false,
   "files": [
     "dist/",
     "lib/"
diff --git a/packages/slate/package.json b/packages/slate/package.json
index c4405c587..958b4b04d 100644
--- a/packages/slate/package.json
+++ b/packages/slate/package.json
@@ -9,6 +9,7 @@
   "types": "lib/index.d.ts",
   "umd": "dist/slate.js",
   "umdMin": "dist/slate.min.js",
+  "sideEffects": false,
   "files": [
     "dist/",
     "lib/"