The successful use of nanoparticulate ZnO in various applications, such as UV-screening agents or as a photocatalyst for the destruction of chemical waste requires the development of techniques for controlling its photocatalytic activity. A widely examined method for achieving this goal has been the incorporation of transition metal oxide dopants. However, experimental studies regarding the effects of particular dopants have often reported conflicting results. For example, some studies have found that cobalt doping of zinc oxide reduces the photocatalytic activity whereas other studies have reported enhanced activity. Such conflicting results are largely due to insufficient characterisation of how the dopants are distributed within the photocatalyst. In this study, transmission electron microscopy with energy dispersive x-ray spectroscopy has been used to determine the distribution of transition metal oxide dopants in nanoparticulate zinc oxide powders that were synthesised by various methods, including mechanochemical processing, hydrothermal processing, and wet chemical precipitation. The results obtained in this study demonstrate the importance of using multiple analytical techniques to characterise the distribution of dopant elements in photocatalytic materials.