Parasite-host relationships can be important for a range of aspects in biology, due to a large number of parasitic species and the influence parasites can have on hosts. For example, parasites can influence the condition and behaviour of their hosts. It is also theoretically predicted that parasite infection can explain variation in animal personality (i.e. among-individual consistency in behavioural responses), although this is still scarcely empirically investigated. In this study, I have examined the relationship between the personality traits of wild-caught three-spined sticklebacks (Gasterosteus aculeatus), and the infection status and load by a microsporid parasite, Glugea anomala. Activity and exploratory behaviour were observed in a novel arena, social and aggressive behaviours in a mirror test, and boldness during a simulated predator attack. Consistent behavioural traits describing personality were identified and analysed for their relationship to infection status. Parasite infection explained variation in social behaviour, where the amount of time fish spent near the mirror correlated positively with parasite load, and in aggression, where attacks launched at the mirror correlated negatively with parasite load. Parasite infection did not explain variation in other personality traits. These results indicate that parasite infection and personality are connected, although future studies are needed to investigate the causality of this relationship.