AbstractWater security is a global concern sharpened by the biggest humanity challenge of climatic crisis. With the end of designing and implementing efficient and sustainable water management strategies, it is necessary to recognize the interdependence and coevolution between natural and social systems and understand how the double way relationships between these systems shape sustainability. The socio‐ecological systems (SES) sustainability approach is an alternative to this end. Conceptual challenges have been identified in the analysis of the sustainability of SES. These challenges include (i) A lack of clarity in the definition of SES sustainability, (ii) the non‐inclusion of some inherent SES characteristics that determine critical thresholds, and (iii) a lack of conceptual frameworks for analyzing the sustainability of SES and water security‐related ecosystem services. This study proposes a conceptual framework, based on a strong sustainability approach, for analyzing SES sustainability focusing on water security and addressing the above‐mentioned challenges. This conceptual development includes three elements: (i) the key thresholds to ensure ecological functionality; (ii) the benefits that society derives from ecological functioning and; (iii) the two‐way relationship between natural capital and social systems. Analyzing these three elements helps identification of different sustainability states of SESs, focusing on water security, in the presence of endogenous or exogenous drivers of change. The conceptualization and operationalization of SES sustainability focusing on water security allows the analysis of the trajectories of change and provides insights into the required water management strategies in the target territory.