This study investigates the psychological and behavioral determinants of Collaborative Fashion Consumption (CFC) in India by integrating the Theory of Planned Behavior (TPB) and the Big Five Personality Model (BFM). Using structural equation modelling (SEM) with path analysis on a sample of 400 respondents, the research examines the influence of attitude (CFCA), sustainable norms (SNCFC), perceived behavioral control (PBCCFC), and personality traits—openness, conscientiousness, extraversion, agreeableness, and neuroticism—on collaborative fashion consumption intention (CFCI) and its subsequent effect on behavior (CFCB). The model demonstrated excellent fit (χ² = 14.485, df = 6, GFI = .993, CFI = .996, RMSEA = .060) and explained 77.3% of variance in CFCI and 77.8% in CFCB. Results revealed that attitude, openness, agreeableness, and perceived behavioral control were strong predictors of intention, while sustainable norms enhanced intention but negatively influenced behavior directly, indicating a value–action gap. Intention emerged as the strongest determinant of behavior (β = .998), confirming TPB’s central premise. The findings highlight the need for attitude-focused, accessible, and personality-aligned strategies to promote collaborative consumption in the Indian fashion sector, while recommending caution against over-reliance on normative pressure that may deter actual engagement.