Increased demands for sustainable apparel products require research to understand better how to encourage sustainable buying behavior effectively, especially in the understudied areas of cross-cultural research. This study, which includes respondents from the UK, US, and China (total n = 711) who completed an online survey, explores determinants of behavioral intention toward sustainable apparel products (SAP). This paper contributes to examine both consumer characteristics (shopping values, consciousness of sustainability, perceived consumer effectiveness, and environmental knowledge) and marketing perspective (evaluation criteria of SAP) determinants for encouraging sustainable apparel consumption behaviors. Significant country differences also emerged, indicating the positive impact on behavioral intention to sustainable apparel products across three countries. Results of structural equation modeling analysis demonstrated there were differences and similarities in the effect of consumers’ characteristic factors and marketing perspective factors on SAP behavioral intention among three countries. The results validate that differentiated marketing strategies in the sustainable apparel industry are required when targeting global consumers to boost sustainable apparel consumption and successfully help to remedy the crisis facing our planet and further generation.