Fine prehensile activities are often thought to have been associated with the evolution of the human hand. However, there has been no holistic approach establishing the link between the morphology of the forelimb and grasping ability in living primates. The present study investigated the possible relationships between grasping behaviour and the morphology of the forelimb in strepsirrhines in a phylogenetic context. To do so, grasping behaviour during feeding and the shape of the long bones of the forelimb were analysed for 22 species of strepsirrhines. The data obtained show that there is a phylogenetic signal in forelimb morphology in primates in relation to grasping behaviour, but also that there is a marked co-evolution between grasping behaviour and the shape of the humerus and radius. This latter finding suggests a functional association between grasping and forelimb shape, which in turn suggests that bone shape constrains or facilitates behaviour. This result may permit future inferences to be made regarding this behaviour in extinct species and deserves further examination in more detail.