This article contributes to the conceptual and methodological strengthening of the study of tourism as a complex phenomenon using systems thinking. It is aimed at supporting decision-making for tourist destinations’ planning and management. Few authors provide a schematic model of how tourism works, and among them, even fewer expressly use a systemic approach. However, nobody presents a methodology for their models’ analytical application to bridge theory and practice. The integrative model (iModel) fills this gap. It is developed through a review of previous models, research in Belgian, German and Ecuadorian cases, discussion in experts’ panels and supported by a long experience in destination development in Ecuador. Main contributions are 1) the introduction of a model of tourism as a dynamic complex system based on the functions performed by the actors involved in the tourism experience; and 2) the presentation of a methodology to apply the model-as-a-tool for decision-making support in tourism practice.