For over a decade, payment for ecosystem services (PES) programs has been designed in several countries, the analysis of these programs in recent years highlights the importance and timeliness of the tool. Taking local context into account stands out among the most significant recommendations for the design and implementation of PES programs. However, no clarity or consensus has emerged about how to define and approach "context". This article proposes to address this issue using the socio-ecological systems (SES) framework. We present conceptual interpretations of context and define and validate the primary set of variables for its characterization. Our analysis is based on a literature review and surveys of people who have implemented these programs in Mexico. We propose "focal", "very significant", and "significant" variables, which allow us to define local context within the framework of PES programs. The proposed focal variables are a) forest cover, b) opportunity cost, c) livelihood and productive diversification, d) pro-social and pro-environmental motivations and attitudes, e) confidence and cooperation, f) traditional management practices, g) internal organization on the local level, h) land tenure, and i) rules for the management and use of natural resources.