MD3, MD 3 or MD-3 can mean: Dätwyler MD-3 Swiss Trainer, a Swiss light aircraft Flyitalia MD3 Rider, an Italian ultralight aircraft Maryland's 3rd congressional district, a United States electoral region Maryland Route 3, a United States highway MD3 (file format) Material Design 3 (a.k.a. Material You), a design language by Google introduced in 2021 with Android 12