This study aims to measure the effect of social media marketing and perceived service quality on online purchase intention that is mediated by consumer trust toward Airpaz.com. The sample obtained in this study was 214 samples. Respondents are customers who had made transactions at Airpaz.com using payments in Indonesian Rupiah. Partial least squares structural equation modeling (PLS-SEM) was used to analyze the collected data. The outer model test proved the reliability and validity of the constructs, as well as the inner model, proved the hypotheses. The results showed that as partial social media marketing has a positive and significant effect on consumer trust, it has no significant impact on online purchase intention. The perceived service quality has a positive and significant impact on consumer trust and online purchase intention. Likewise, consumer trust has a positive and significant effect on online purchase intention. The hypotheses are supported since social media marketing, and perceived service quality has a positive and significant impact on online purchase intention, mediated by consumer trust. The findings can direct Airpaz.com or other online retailers to increase their promotion and marketing by using social media. And also, they improve their service quality to create customer trust and online purchase intention, especially for Airpaz.com, which has a smaller market share in Indonesia and smaller social media followers compared to its competitors. These findings showed that social media marketing was not always directly influenced by online purchase intention, but the correlation needs the trust variable as the mediator