Jetpack Compose is a modern toolkit for building native Android user interfaces that simplifies and accelerates development with less code. It uses composable functions to define the UI programmatically based on data dependencies rather than focusing on the construction process. Jetpack Compose provides Material Design elements out of the box and uses a hierarchical layout system to compose functions within other functions to build the UI. It also supports features like lists, grids, animations and modifiers to customize the UI.