Higgs boson pair production will play an important role in the LHC's physics program in the coming years. It is the most important channel for measuring the self-coupling of the Higgs boson. Precise theoretical predictions are essential for this. NLO QCD predictions show a relatively strong dependence on the top quark mass renormalization scheme. This talk presents and summarizes the latest theoretical predictions, with a focus on recent developments in calculating NNLO QCD corrections.