A set of transition-metal-free heterogeneous catalysts for the epoxidation of alkenes with hydrogen peroxide was studied by means of High-Throughput Experimentation. The catalysts were tested with a range of substrates. Gallium oxide displayed the highest epoxidation activity with all tested alkenes, followed by Ga-MCM-41. The reaction conditions were optimised by investigating the effect of the solvent in which the epoxidation takes place. Considerable improvements in the epoxide yields were obtained in the processes catalysed by Al MCM-41, Ga-MCM-41 and zeolite USY(2.6). This work confirms the versatility of HTE for studying catalytic systems.