This quantitative study employed Partial Least Squares Structural Equation Modeling to examine the complex relationships between six motivational dimensions and sports participation among individuals with a disability. The research involved 150 Iranian individuals with a disability stratified by disability type, including deaf individuals, blind or visually impaired individuals, individuals with limb amputations or impairments, and those with other physical disabilities. Data collection utilized an adapted 26-item Sport Motivation Scale (SMS-II) administered through an online questionnaire platform with comprehensive accessibility support for participants who required additional support. Through rigorous analysis, the path analysis revealed that motivational dimensions interact in hierarchical patterns, with intrinsic motivation serving as the dominant driver of participation, followed by identified regulation, introjected regulation, and integrated regulation. The findings demonstrate that individuals with a disability operate under distinct motivational dynamics compared to populations without a disability, where autonomous and internalized forms of motivation substantially outweigh external incentives or controls. This research contributes nuanced understanding of how psychological motivation functions as a critical mechanism influencing athletic engagement, revealing that individuals with a disability respond most favorably to motivational strategies emphasizing genuine interest, personal relevance, social support, and identity integration rather than external rewards or compliance mechanisms.