Although cultural similarity is often considered to facilitate the development of negotiations from a win-win or value creation approach, the evidence obtained calls this assumption into question. Recognizing negotiation as a critical component of organizational strategic processes, this study challenges the traditional integrative/competitive dichotomy commonly used in negotiation behavior analysis. The study adopts an abductive reasoning approach, enabling an iterative dialogue between empirical observations and existing negotiation theory. From a methodological perspective, the research is positioned as a theory elaboration study, aiming to refine and extend established negotiation frameworks rather than to test predefined hypotheses. Based on 21 in-depth interviews with professional buyers engaged in customer/supplier negotiations at four leading supermarket chains in Costa Rica, which together represent more than 80% of the national supermarket market share in the country. The study examines how the degree of cultural similarity influences the three categories of negotiating actions: inappropriate competitive, acceptable competitive, and integrative. The findings show that greater cultural similarity does foster more integrative actions but does not reduce the occurrence of acceptable or inappropriate competitive actions. These insights are relevant both academically and professionally, particularly in the fields of business and strategic decision-making.