It is often assumed that relatedness with peers and teachers are two developmental factors whose effects are independent of each other. Preliminary research nevertheless suggests that the combined effects of peer and teacher relationships may manifest in various ways, resulting in positive or negative outcomes based on the degree and direction of imbalance in relatedness levels across social partners. Relatedly, complex social ecology models have underlined the importance of analyzing such combined effects; however, there has been limited research proposing operationalizations of such processes. The present research aims to address the substantive issue of how peer and teacher relatedness intersect in influencing well-being and school engagement by introducing a novel methodological framework for operationalizing complex social ecology, specifically cubic response surface analysis. The validity of this substantive-methodological synergy was examined in Study 1 (N = 643 students, 75% female, aged 15–18) and cross-validated in Study 2 (N = 493 students, 66% female, aged 10–18) with a focus on various combinatory processes related to school relatedness. Overall, results suggested that peer relatedness was beneficial to student well-being and engagement when accompanied by teacher relatedness. However, there was limited support for the positive effects of peer relatedness in the absence of teacher relatedness. Conversely, teacher relatedness was sufficient to foster school engagement, yet it did not contribute to well-being in the absence of peer relatedness. The implications highlight the interdependency of both peer and teacher relatedness in fundamental research and interventions and emphasize the added value of cubic response surface analysis for investigating intricate dynamics within complex social ecologies. (PsycInfo Database Record (c) 2025 APA, all rights reserved)