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.