Beyond-the-Standard-Model Higgs physics using the ATLAS experiment

The ATLAS and CMS experiments at the Large Hadron Collider discovered a new particle, with a mass of 125GeV and properties compatible with that predicted for the Higgs boson by the Standard Model. Understanding if this particle is part of a larger and more complex Higgs sector is one of the major challenges for particle physics experiments. In this report, an overview on latest results obtained on LHC Run-1 data by the ATLAS experiment on Beyond-the-Standard- Model Higgs searches is presented. Searches for new physics in the Higgs sector are presented and interpreted in well-motivated theoretical frameworks, including the two-Higgs-doublet Models and the Minimal and Next-to-Minimal Supersymmetric Standard Model.