I will present the next-to-leading order QCD Corrections to the loop-induced gg -> ZZ production channel including full top quark mass effects. Results for ZZ production via loop(s) of massless quarks have been known for some time, while the two-loop amplitudes for the production via massive quark loops became available only in the last few years. In this work, we combine the two-loop virtual amplitudes with one-loop real radiation to study the phenomenological impact of the top quark mass corrections. For this work, the loop integrals appearing in the virtual amplitude are computed numerically using sector decomposition, I will discuss some of the recent algorithmic improvements that have been used to accelerate their computation.