Decision Support Systems (DSSs) in production agriculture are computer software programs that make use of models and other information to make site-specific recommendations for farm management-related activities. Major advances have been made in developing DSS for agriculture, particularly with respect to incorporating climate forecasts into farmers’ decision-making process. This chapter describes DSSs in agriculture, focussing on the importance of a participatory approach in DSS development. The chapter offers examples of climate-based DSS for crop and land management, pest and disease management, and livestock (dairy) management. The chapter reflects on lessons learned in the process of developing climate-based DSS. Finally, the chapter looks ahead to future research trends in this area.