This study investigates the influence of viral marketing on the purchase intention of high-end cosmetic products, emphasizing the mediating role of attitude on behavior. The rapid development of the internet and social media has significantly changed marketing strategies, with viral marketing currently being executed by many cosmetic brands. Viral marketing utilizes information, entertainment, irritation and source credibility to engage consumers and drive purchase decisions. However, preliminary research suggests a gap between theoretical benefits and practical outcomes, highlighting the skepticism of consumers of high end cosmetic products towards viral marketing. This study aims to bridge this gap by identifying the dimensions of viral marketing that have the most influence on purchase intention and attitude towards behavior. Despite its potential, not all viral marketing efforts are successful in driving purchase intention, so a deeper understanding of the factors at play is needed. This study employs a quantitative approach, using structural equation modeling (SEM) to analyze data collected from 100 women who have purchased high-end cosmetic products in the past six months. Findings reveal that source credibility is the most significant variable in viral marketing that influencing both purchase intention and attitude towards behavior on high end cosmetics product, Source credibility enhances trust and perceived value, leading to a stronger positive attitude towards the product and higher purchase intentions.