This paper reviews the literature on growth in reptiles. The current consensus is that growth data for small and medium-sized reptiles are best fitted by logistic-by-mass equations, data for larger reptiles by the von Bertalanffy equation. Experiments on the relationships between behavioural thermoregulation, food consumption and growth in both the laboratory and field are described, and an account is given of some recent work on individual differences in growth rates and their adaptive significance. In general, it may be said that in almost all areas of biology relating to growth, less is known about reptiles than about equivalent phenomena in fishes.