diff --git a/packages/packemon/src/Package.ts b/packages/packemon/src/Package.ts
index b9f3f2b..c1eb244 100644
--- a/packages/packemon/src/Package.ts
+++ b/packages/packemon/src/Package.ts
@@ -489,6 +489,16 @@ export class Package {
 		// Sort and flatten exports
 		exportMap = sortExports(exportMap);
 
+		// Fill in missing defaults
+		const conditionsNeedingDefaults = ['browser'];
+		for (const condition of conditionsNeedingDefaults) {
+		  for (const path of Object.keys(exportMap)) {
+			if (exportMap[path][condition]) {
+			  exportMap[path][condition].default = exportMap[path].default;
+			}
+		  }
+		}
+
 		if (isObject(this.json.exports)) {
 			Object.assign(this.json.exports, exportMap);
 		} else {