Some ectothermic animals are subject to changes of body temperature during routine activity. How are they able to maintain co-ordinated behaviour? Analysis of the available evidence on the effects of temperature on the vestibulo-ocular reflex suggests that there will be a degree of automatic temperature compensation. Temperature will increase the gain of some components of the reflex, and decrease the gain of others resulting in a reduced temperature sensitivity of the overall reflex. It is suggested that the cerebellum may provide the balance of temperature compensation required to maintain adequate reflex function. The hypothesis is that type III (bidirectionally sensitive) Purkinje cells receive temperature information as a common-mode signal from the opposing labyrinths, and use this information to regulate the gain of the vestibulo-ocular reflex pathway.