This paper introduces a theoretical framework intended to define the nature, structure, and function of external team contexts. The external team context is defined as the resources, stimuli, elements, and features that are part of a broader multilevel system but exist outside the team’s boundaries and that influence (and are influenced by) the team in temporally dynamic ways. The proposed framework seeks to understand all such contexts in terms of three continuous dimensions. First, munificence is the portfolio of resources that exist in the external team context and is composed of the quantity, quality, and interconnectedness of resources. Second, temporal dynamism is the manner in which resources in the external team context change over time and is composed of valence, rate of change, and continuity. Third, spatial variability is the span of levels at which resources exist within the broader system and is composed of origins, systemic distance, and bond strength. Contextual complexity is thus a function of munificence, temporal dynamism, and spatial variability. The framework posits that nearly all discrete contextual stimuli, events, and features can be understood in terms of these dimensions and subdimensions. In doing so, the framework integrates and reconciles several diverse strands of research, spanning different levels and disciplines, in a way that is parsimonious, precise, and falsifiable. The framework offers many insights for theory, empirical research, and practice and helps complement and advance existing theories and frameworks. A preliminary measure of context is also provided to help researchers apply and test the framework.