Abstract: Following the discovery of the Higgs boson at the Large Hadron Collider (LHC), a major goal is to characterize the properties of this new particle. The Higgs itself is a potential portal to new physics, providing connections between the Standard Model of particle physics and new phenomena, such as signatures of dark matter. Searches for new decays of the Higgs boson will be described using data collected by the ATLAS experiment and future prospects will be discussed.