SIMSSR is a new whole-farm model that simulates the effect of farm management, genetics, and climate on emissions and other sustainability attributes from small ruminant systems in Europe. It covers over 25 breeds and a diversity of production systems. SIMSSR simulates the effect of management, genetics, soil, and climate on farm environmental performance like nitrogen and carbon losses/sinks. It also provides basic economic outputs and other sustainability attributes. The model is process-based, generic, and written in DELPHI software to allow running scenarios under different current and future conditions.