This study attempts to investigate whether Social Media Marketing Activity (SMMA) carried out by companies / brands have a positive impact on their brand equity, e-WOM distribution on social media and customers' purchase intention. The objective of this paper is to investigate the impact of SMMA towards customers' purchase intention. The researchers tried to survey the results of previous studies to give more benefits to the readers and researchers in this area of study. Research data was collected using an online questionnaire survey of 114 participants of Instagram users in Indonesia. The results of structural equation modelling supported the current model's validity and indicated a positive effect of SMMA towards brand equity. Moreover, brand equity had a positive impact on e-WOM; and e-WOM maintained a positive influence towards customers' purchase intention. Finally, SMMA also has showed a direct impact to customers' purchase intention.