"Seasonal Forecast Course Package T.O.P." is a set of online resources whose goal is to enhance knowledge in the theory of seasonal forecasting and operational use of seasonal climate forecasts. The course package has two audiences. The first is training institutions, to facilitate development of additional training courses. The materials and documentations here collected represent the building blocks of a course based on validated contents and user needs. It can also be used by national hydro-meteorological service staff members who wish to improve their climate services competencies or to specialise in seasonal forecasting. For this audience, the course package will provide theoretical and practical knowledge on seasonal forecast and predictability models, climate and data analysis, forecast verification, and specific application of seasonal forecast for agriculture and water management. This website is an online training package developed by the WMO Regional Training Center Italy, Institute of Biometeorology, CNR-National Research Council Rome, Italy, based on a series face-to-face-to-face courses delivered from 2014-17, and provided via a structured website.