In P 4 3 32 LMNO, there are two distinct types of vacant O h sites: 4a and 12d sites which are surrounded by 3Mn 4+ and 3Ni 2+ and 5Mn 4+ and a Ni 2+ , respectively. The lowest energy relaxed configurations of Li i and Ni i interstitials are in the 12d sites, whereas that of Mn i are in the 4a sites. While the electrostatic interactions form a key contributor to the observed interstitial site preference, we find charge localisation, coordination environment and (potential) dumbbell formation to also play a key role.