Due to the importance of wind energy in the fight against climate change and the nowadays challenges faced by developed countries, associated with the management of the existent infrastructure and the need to harvest the energy available at offshore sites, structural monitoring of wind turbines gained special relevance. Consequently, this research topic has been deeply explored in the research unit CONSTRUCT at the Faculty of Engineering of the University of Porto (FEUP). The present contribution describes the main concepts associated with the structural monitoring of wind turbines in different environments, with special focus on strategies for evaluating fatigue consumption and tracking the most relevant modal properties. Both monitoring goals present several challenges due to the particularities of these structures, with moving components, which become especially demanding when the wind turbine operates on the top of a floating platform. This paper presents recently proposed processing methodologies and promising results that prove the pivotal role of structural monitoring in this very active field.