Increasing global temperatures over the coming decades are predicted to adversely affect tropical forest vegetation, in part by increasing the temperature-dependent inhibition of photosynthesis. Few studies have measured the temperature sensitivity of photosynthesis across a range of habitats. In the present study, we measured the instantaneous temperature response curves for the carbon assimilation ( A net) and electron transport (ETR) rates, in situ on mid-storey branches of 11 tree species in a seasonally dry tropical forest in the Central Western Ghats, India. We also determined PSII thermal tolerance ( T 5 and T 50) on the leaves from the same branches. The data demonstrate that there is an inverse correlation between T 5 and the thermal optima of A net ( T opt, Anet) ( p=0.005), i.e. lower T opt, Anet was associated with greater PSII heat stability (higher T 5) and vice versa but no relationship found between T 50 and T opt, Anet. These data not only confirm that both T opt and T 50 ( T 5) vary significantly between species but also provide new insights into relationships between the assimilation temperature range and optimum, and the photosystem integrity parameters T 5 and T 50.