It is well established that matching unfamiliar faces is highly error prone, even under seemingly optimal conditions. This thesis shows large individual differences in unfamiliar face matching. Across several visual cognition tasks, the best predictor for this variability was recognition of inverted faces, regardless of whether they were familiar or unfamiliar. In stark contrast, there was no relationship between upright familiar and unfamiliar face processing. Moreover, the ability to match faces was unrelated to the ability to reject these faces, unless they were upright familiars. Therefore, the processes involved in upright unfamiliar face processing appeared to be qualitatively similar to those underlying the recognition of inverted familiar and unfamiliar faces, but very different to those responsible for upright familiar face processing. Finally, the presence of a second face severely impaired matching a target person, particularly when they were presented close together. The implications of these findings for the forensic field are discussed.