Online coupled meteorology atmospheric chemistry models have undergone a rapid evolution in recent years. Although mainly developed by the air quality modelling community, these models are also of interest for numerical weather prediction and climate modelling as they can consider not only the effects of meteorology on air quality, but also the potentially important effects of atmospheric composition on weather. This report provides the main conclusions from the Symposium on “Coupled Chemistry-Meteorology/Climate Modelling: Status and Relevance for Numerical Weather Prediction, Air Quality and Climate Research” and an overall outcome of the European COST Action ES1004: European Framework for Online Integrated Air Quality and Meteorology Modelling (EuMetChem). It also contains the symposium abstracts and a review of the current research status of online coupled meteorology and atmospheric chemistry modelling, a survey of processes relevant to the interactions between atmospheric physics, dynamics and composition, and highlights selected scientific issues and emerging challenges, which require proper consideration to improve the reliability and usability of these models for three scientific communities: air quality, numerical meteorology modelling (including weather prediction) and climate modelling. It presents a synthesis of scientific progress in the form of answers on eight key questions and recommendations for future research directions and priorities in the development, application and evaluation of online coupled models.