diff --git a/cli/plasmo/src/features/manifest-factory/base.ts b/cli/plasmo/src/features/manifest-factory/base.ts
index 872df5dc2..abc2390f7 100644
--- a/cli/plasmo/src/features/manifest-factory/base.ts
+++ b/cli/plasmo/src/features/manifest-factory/base.ts
@@ -176,7 +176,9 @@ export abstract class PlasmoManifest<T extends ExtensionManifest = any> {
 
   get dependencies() {
     ok(this.packageData)
-    return this.packageData.dependencies
+    // to support npm workspaces (mono repos) we need to fallback to
+    // peerDependencies because dependencies will never exist
+    return this.packageData.dependencies ?? this.packageData.peerDependencies
   }
 
   get devDependencies() {
diff --git a/core/parcel-runtime/src/index.ts b/core/parcel-runtime/src/index.ts
index 9e8a4437f..2f1c980b3 100644
--- a/core/parcel-runtime/src/index.ts
+++ b/core/parcel-runtime/src/index.ts
@@ -27,6 +27,7 @@ export default new Runtime({
       .getConfigFrom<{
         dependencies: Record<string, string>
         devDependencies: Record<string, string>
+        peerDependencies: Record<string, string>
       }>(
         join(process.env.PLASMO_PROJECT_DIR, "lab"), // parcel only look up
         ["package.json"],
@@ -36,7 +37,8 @@ export default new Runtime({
       )
       .then((cfg) => cfg?.contents)
 
-    const hasReact = !!pkg?.dependencies?.react || !!pkg?.devDependencies?.react
+    // npm workspaces mono repo's do not have dependencies or devDependencies (they are defined in a parent directory), fallback to peerDependencies
+    const hasReact = !!pkg?.dependencies?.react || !!pkg?.devDependencies?.react || !!pkg?.peerDependencies?.react
 
     return {
       hasReact