Previous research states that viral marketing has an important role in increasing consumer purchasing intentions, viral marketing can also encourage increased brand awareness. This research aims to analyze the relationship between Viral marketing and purchasing decisions, Brand awareness and purchasing decisions, and Viral marketing and purchasing decisions. This research method is quantitative through surveys, research data was obtained by distributing online questionnaires to 720 selected online shop customers in Indonesia using a simple random sampling method, and the online questionnaire was designed using statement items with a Likert scale of 1 to 7. Data analysis used a structural equation model based on covariance (CB-SEM) with SmartPLS 4.0 software to analyze research data. The independent variables are viral marketing and brand awareness, and the dependent variable is purchasing decisions. The stages of data analysis are validity testing, reliability testing, model fit testing, and significance testing of hypothesis testing. The results of this research are that Viral marketing has a positive and significant relationship with purchasing decisions, Brand awareness has a positive and significant relationship with purchasing decisions, and Viral marketing has a positive and significant relationship with purchasing decisions. Viral marketing is one of the factors that can influence purchase intentions. Viral marketing is expected to have multiple effects because many people who receive the message can convey it to tens or even hundreds of other internet users. Brand awareness can influence consumers toward purchasing decisions, which states that brand awareness has a significant influence on purchasing decisions.