We present the GiBUU model for neutrino nucleus scattering: assuming impulse approximation, this reaction is treated as a two step process. In the initial state step, the neutrinos interact with bound nucleons. In the final state step, the outgoing particles of the initial reaction are propagated through the nucleus and undergo final state interactions. In this contribution, we focus on the validation of the initial and final state interaction treatment in GiBUU using experimental data for pion-nucleus, photon-nucleus and electron-nucleus scattering.