The second period of data taking at the Large Hadron Collider (LHC) has provided a large dataset of proton-proton collisions that is unprecedented in terms of
its centre-of-mass energy of 13 TeV and integrated luminosity of almost 140/fb. These data constitute a formidable laboratory for the search for dark matter in the context of the LHC. The most recent results of the ATLAS Collaboration will be presented. In absence of significant observations, interpretations of the results in terms of exclusion limits in different models of new phenomena will be discussed.