The GROMOS software for biomolecular simulation is developed and maintained by research groups in Stuttgart, Vienna and Zurich. The aim of this year’s workshop is twofold. On the one hand, participants who are new to GROMOS get a focused introduction to programming, the structures of GROMOS and the main programming rules. On the other hand, participants with some experience already get more insight into the code and work together to tackle specific issues and improvements in the code. The whole is complemented with discussions about the documentation, force fields and the gitlab repository.