Social information processing theories suggest that aggressive individuals may exhibit hostile perceptual biases when interpreting other’s behaviour. This hypothesis was tested in the present study which investigated the effects of physical aggression on facial expression identification in a sample of healthy participants. Participants were asked to judge the expressions of faces presented to them and to complete a self-report measure of aggression. Relative to low physically aggressive participants, high physically aggressive participants were more likely to mistake non-angry facial expressions as being angry facial expressions (misattribution errors), supporting the idea of a hostile predisposition. These differences were not explained by gender, or response times. There were no differences in identifying angry expressions in general between aggression groups (misperceived errors). These findings add support to the idea that aggressive individuals exhibit hostile perceptual biases when interpreting facial expressions.