Double Field Theory describes the NS-NS sector of string theory in a T-duality invariant fashion. This theory lives on a doubled spacetime and has a local gauge symmetry when differential constraints are imposed on fields and gauge parameters. After a short introduction of Double Field Theory I will introduce a vielbein formulation of this theory and explain how half-maximal gauged supergravity in four dimension are obtained by compactification of Double Field Theory. I will then briefly sketch how dynamical non-geometric fluxes and Ramond-Ramond fields can be included in this context.