This study aims to explore factors that have impact on purchase decision on a social commerce, viz., social media Instagram. Thus, several dimensions namely eWOM referral, celebrity endorsement, information quality, brand satisfaction, brand trust and brand attachment are identified and examined. This research uses SEM method and LISREL 8.80 application. Data was collected using questionnaires with ikert scale. The result from 350 respondents shows that a significant positive correlation exists between eWOM referral and purchase intention, information quality and brand satisfaction, information quality and brand trust, brand satisfaction and brand attachment, brand satisfaction and purchase intention, brand trust and purchase intention, brand attachment and purchase decision, and also between purchase intention and purchase decision. © 2020 by IGI Global. All rights reserved.