This study aims to provide and validate a theoretical framework for localized guerrilla marketing for sports organizations with financial and cultural constraints, focusing on the Iranian Bodybuilding and Fitness Federation. This research was conducted using a qualitative method based on Strauss and Corbin method. Data were collected through semi-structured interviews with 15 sports marketing experts, federation managers, and university faculty members and analyzed using a three-stage process of open, axial, and selective coding to identify key components and develop a theoretical model for the effective application of guerrilla marketing in Iranian sports organizations. The final research model was structured around five main axes: (1) causal conditions, including innovative ideas and the need for brand differentiation; (2) contextual conditions, including cultural and financial constraints, and enabling factors such as modern technologies; (3) intervening conditions, including organizational support or resistance and the federation’s internal capabilities; (4) strategies, consisting of external actions, such as collaborating with influencers, and internal actions, such as directly engaging with the audience; (5) consequences, including macro-level outcomes, such as rapid social media diffusion, and organizational outcomes, such as customer loyalty. The originality of this research lies in providing a localized theoretical framework of guerrilla marketing for Iranian sports federations with financial and cultural constraints. Using grounded theory and qualitative data analysis, this study goes beyond a descriptive case study to provide a generalizable model that sports organizations in emerging economies or resource-constrained environments can use to adapt guerrilla marketing strategies to their own circumstances.