Here we demonstrate stabilization of the hexagonal manganite phase through high entropy compositions of RMnO3, with R = Y, Gd-Er, resulting in materials with excellent oxygen storage capacity and outstanding oxidation kinetics. High configurational entropy favors single-phase hexagonal materials with oxygen storage capacity comparable to the best reported single R compounds. Importantly, the oxidation kinetics is significantly improved, and both the capacity and kinetics are insensitive to the exact rare earth cation composition. The improved kinetics are discussed with respect to structural disorder resulting from high configurational entropy, and the size of the R 3+ cations causing an expansion of the ab-plane. Finally, sustainability aspects are addressed.