Acclimation to environmental cues helps plants cope with climate change. We assessed the temperature response of leaf photosynthetic parameters in wheat under contrasting water regimes and growth temperatures (Tgrowth). Two independent experiments were conducted under controlled conditions. In Experiment 1, two wheat genotypes were subjected to well-watered or drought-stressed treatments; in Experiment 2, the two water regimes combined with high, medium and low Tgrowth were imposed on one genotype. Parameters of a biochemical C3-photosynthesis model were estimated at six leaf temperatures for each factor combination. Photosynthesis acclimated more to drought than to Tgrowth. Drought reduced photosynthesis by reducing its optimum temperature (Topt) and the values at Topt of light-saturated net photosynthesis, maximum rate of electron transport (Jmax), and maximum rate of carboxylation by Rubisco (Vcmax). Topt for Vcmax was up to 40°C under well-watered conditions but 24-34°C under drought. The reduction of photosynthesis by drought varied among Tgrowth but was similar between genotypes. The temperature response of photosynthetic quantum yield under drought was not only attributed to photorespiration but more to alternative electron transport for photoprotection. The commonly used photosynthesis models, which ignore acclimation responses to drought and Tgrowth, strongly over-estimate leaf photosynthesis under variable temperature and drought.