<p>Over the last few years, changes in land use and climate have led to fluctuations in water resources. These changes have been affecting streamflow, the environment, drinking water, and agriculture. This research aims to determine how climate change and land use are likely to impact streamflow in the Talar basin between 2020 and 2050. This research analyzed data based on the CMIP6 climate change scenarios, as well as land use predictions for 2035 and 2050. First, the Soil and Water Assessment Tool (SWAT) was applied to predict the impacts of climate and land use on streamflow in the Talar River basin. Model evaluation (e.g. calibration and validation) at the Kiakola station showed that the Nash–Sutcliffe (NSE) had an R² of 0.8 and 0.76, respectively, while at the Shirgah station the values were equal to 0.84 and 0.75. After calibration and validation of the model using the best parameters from 2004–2020, six general circulation models (GCMs) from CMIP6 were downscaled and projected under SSP2-4.5 and SSP5-8.5 scenarios. To downscale GCMs, two widely used methods, namely Delta method (Delta) and Quantile mapping (Qm were used). In this research, the CA-Markov prediction model was used to predict land-use change in two future years, 2035 and 2050. The precipitation and temperature data from climate change scenarios and land use maps were used in the SWAT model to predict mean monthly streamflow during 2020–2035 and 2020–2050. The results indicated that there was a decrease in average monthly streamflow due to different land use changes, such as the urban and agricultural land expansion. In the future, changes in land cover (LULC) and climate change will likely impact streamflow. The main drivers of LULC change include farming expansion, deforestation, settlement expansion, land orchard policy, and infrastructure development.</p>