The aim of the present study is vertical coopetition: a novel strategy in supply chain relationships (a meta-synthesis of antecedents and consequences). In terms of implementation, this research is mixed-methods (qualitative-quantitative). In the qualitative phase, using the meta-synthesis method and analyzing 32 selected articles from معتبر scientific databases (2000–2026), initial concepts were extracted and organized into sub-themes and main themes. In the quantitative phase, Shannon entropy technique was used to measure the density and conceptual dispersion of the themes. For data analysis, meta-synthesis was employed in the qualitative phase and Shannon entropy technique in the quantitative phase.The findings in the antecedents section led to the identification of five main themes: “relational capability” (with the highest conceptual density), “relational asymmetry,” “supply chain structural constraints,” “environmental and institutional pressures,” and “economic pressure” (with the lowest conceptual density). In the consequences section, eight main themes were also identified, ranked by conceptual density as follows: “relationship reconfiguration,” “competitive reconfiguration,” “firm performance reconfiguration,” “knowledge management and innovation reconfiguration,” “supply chain efficiency reconfiguration,” “value redistribution,” “resource and dependency reconfiguration,” and “risk redistribution.”The results show that vertical coopetition is a paradoxical and multidimensional phenomenon that emerges both through capability building and learning within relationships and in response to power asymmetry, supply chain structural constraints, and environmental pressures. Its consequences are also distributed across relational, competitive, performance-related, knowledge-based, value-based, and risk-related dimensions, and are highly contingent on context, power balance, and the quality of relational governance.