The wheat is one of the main agricultural products that will be affected by climate change. The aim of the study is to determine the effect of climate change on wheat yield in Porsuk Creek Watershed. In this study, wheat yield analyzes in the Porsuk Creek watershed had been conducted using the past (2016-2017) and future (2020-2100) climate data produced according to the optimistic (RCP4.5) and pessimistic (RCP8.5) scenarios of the HadGEM2-ES global climate model, with the help of the WOFOST model. In the Porsuk Creek Watershed, a +23.8% difference for 2016 and a +1.2% difference for 2017 was determined between the observed and predicted by WOFOST model wheat biomass values (2017 values>2016 values and estimated>observed). According to the optimistic scenario results in the watershed, 0.73% wheat yield increase is expected in the near future (2020-2045). In all other remaining periods; it is estimated that there will be a decrease in wheat yields (between 0.43-1.5%). Compared to reference period (1970-2000), the climate change in the creek watershed will occur in the manner of temperature and precipitation increases in the future. As a result, although WOFOST tends to predict wheat yields greater than the observed values, it is thought that the model can be used with confidence to predict future wheat yields. As a result of this study, important data about the planning of wheat agriculture were produced by estimating the plant yield for the use of decision makers.