The Working Group on Multispecies Assessment Methods (WGSAM) aims to advance the use of knowledge on predator‐prey interactions for fisheries and ecosystem management. This report summarises the achievements of a 3‐year cycle, focusing on the evaluation of key‐runs and the skill assessment of multispecies models. WGSAM released key‐run models for various ICES regions, including the North Sea, Baltic Sea, and Georges Bank. The models for the North Sea and Baltic Sea provided updated estimates of predation mortality for key commercial stocks, which have been integrated into stock assessments. Methods to assess the skill of multispecies models were established, focusing on understanding model prediction differences, choosing appropriate criteria, and comparing modelled dynamics with true dynamics. A publicly available simulated dataset was developed for skill assessment and model comparison. Approaches for generating advice by comparing and combining multiple models were evaluated, including the R‐package “EcoEnsemble” and methods for combining models with multiple drivers. Further developments included the ʺFishStomachsʺ R‐package for stomach contents data, the MFDB data‐handling package, and the growth of multispecies and ecosystem models. Efforts also focused on the impact of temperature on marine ecosystems, linking fisheries management with Good Environmental Status, developing new foodweb indicators, and assessing management goals and harvest control rules.