The Internet has propelled the marketing field, and viral marketing has become a potent strategy to enhance the purchase intention in today's market. The current study was aimed at finding out how the brand association creates an impact on the viral marketing and consumers' purchase intention relationships in the cosmetic sector. Under the quantitative technique, the research was carried out in the town of Udaipur, Tripura, India. There are 340 respondents who will be chosen under the simple random sampling technique. The structured questionnaire was used to gather the data by the female respondents following the ethical considerations of the research and analysis of the data was done using structural equation modelling in AMOS 21. Mediation analysis between viral marketing, brand association and purchase intention in the cosmetic sector has been performed to cheque the interrelationship between them. The findings reveal that there is a presence of a partial mediation effect due to the involvement of brand association in between the effect of viral marketing towards the purchase intention that emphasises the importance of building and maintaining strong brand associations to enhance the impact of viral marketing strategies. The investigation provides new empirical data to the small body of literature on digital marketing and consumer behaviour in the north eastern part of India.