The marketing landscape has shifted from traditional methods to digital approaches. In the digital era, the popularity of social media as a marketing tool has increased alongside the growing awareness of its potential as a marketing platform. Accordingly, Instagram Ads have been widely used in education as a marketing communications tool. However, the use of Instagram Ads as a promotional channel in higher education has not been able to increase the number of prospective students. To increase the number of prospective students and understand the factors that can influence the purchase intention of prospective students through Instagram Ads, it is necessary to know the key factors that can increase the purchase intention so that better and more effective marketing strategies can be formulated. This research aims to determine the influence of Instagram Ads with the variables of Credibility, Irritation, Informativeness, and Entertainment on Purchase Intentions through Affective Customer Engagement, Positive Online Word of Mouth (WOM) and Intentions Interactions. The method used in this research is quantitative. The types of data needed in the research are primary and secondary data collected using a questionnaire via Google Form which was distributed to 428 Instagram users who had seen or received Instagram Ads content from one of the private Universities in Bandung. The sampling was carried out using a non-probability sampling method, purposive sampling type. The data analysis technique uses SEM – PLS (Partial Least Square) processed using Smart PLS software. The results of the research show that Affective Customer Engagement has a significant effect on Positive e-WOM and Intentions Interactions. Positive e-WOM and Intentions Interactions have a significant effect on driving Purchase Intentions. An Indirect influence on Purchase Intentions is also found in a structural model. If ranked, the most influential are Affective Customer Engagement, Entertainment and Informativeness. Meanwhile, Credibility and Irritation did not affect significantly Suggestions for Instagram ad promotion to focus more on the main factor - Affective customer engagement- that influences the purchasing intentions of potential new students. Besides, it is expected to be able to provide entertainment and more informative content because the research results show how entertainment and informativeness will have an indirect effect on propelling enrolment. Apart from that, building interactions with prospective new students is also necessary considering that Intentions Interactions also affect enrolment decisions. For future research, it is recommended to consider adding other factors that can increase purchase intentions and it is hoped that we can use the current model for further research on other social media platforms.