An exciting new sub-field has emerged in particle physics: testing fundamental features of quantum mechanics in collider experiments. A prominent initial result is recent observation of quantum entanglement between top-quark pairs: the first measurement of entanglement between free quarks, and the highest-energy quantum information experiment to date. In this talk, I will discuss the various aspects of quantum mechanics that we can test, and present ATLAS and CMS measurements of entanglement, outlining the experimental challenges, and shortcomings in current modelling tools. Building on this observation, I will discuss how future measurements of quantum information phenomena at the LHC may be used to set constraints on new physics, and even probe the nature of quantum theories themselves.