The temperature dependences of net photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E) and dark respiration (RD) of four neem (Azadirachta indica A. Juss) provenances of 11 years old were measured in three seasons of 2006 in the dry-hot valley area of southwest China under field conditions. The results indicated that PN of four neem provenances showed clear parabolic responses with the increase of temperature. The optimum temperature of PN was around 25°C in initiation stage and 30°C in prosperous stage except for neem originating from Jodhpur (MA) provenance which was very close to the mean daily temperature of the preceding week while it was around 27°C (MA provenance excepted) in last stage which was rather close to the mean daily maximum temperature of the preceding week. The optimum temperature for PN of MA provenance was about 2–4°C higher than that of the other three neem provenances in prosperous stage and last stage. According to the fitted parameters of photosynthetic temperature response curves, the photosynthetic performance in prosperous stage was more sensitive to temperature changes than that in initiation stage and last stage while the photosynthetic performance of neem originating from MA provenance was less sensitive to temperatures than that of neem originating from Kalyani, New Delhi and Kulapachta provenances in each growing stage. Furthermore, the temperature ranges for PN of MA provenance were much wider than those of the remaining provenances in each growing stage. These differences in photosynthetic temperature acclimation between neem provenances not only reflected temperature regime of native habitats of these provenances but suggested that MA provenance could be more tolerant to extreme temperatures compared with the remaining provenances. The temperature response curves of gs and E were generally similar in form in the same growing stage for all neem provenances; however, shape of the response curves in initiation stage and last stage was similar to parabolic curve while that in prosperous stage was similar to linear relation. The temperature for maximum gs and E in initiation stage was close to the optimum temperature of PN, but the maximum gs reached at much lower temperature than PN and E in last stage. The response of RD to temperature increased exponentially with temperature; however, there were obvious differences in different growing stages. RD in initiation stage was markedly higher than that in prosperous stage and last stage at a given temperature for four neem provenances. These results suggested that four neem provenances can acclimate to their growing environment through changed photosynthetic ecophysiological responses in course of subjecting to seasonal variation of temperature.