diff --git a/packages/realm/android/build.gradle b/packages/realm/android/build.gradle
index 4469445ba..3ffcaa6d1 100644
--- a/packages/realm/android/build.gradle
+++ b/packages/realm/android/build.gradle
@@ -22,6 +22,12 @@ rootProject.allprojects {
 apply plugin: 'com.android.library'
 
 android {
+
+    // Conditional for compatibility with AGP <4.2.
+    if (project.android.hasProperty("namespace")) {
+        namespace 'io.realm'
+    }
+
     compileSdkVersion 28
 
     defaultConfig {