The pandemic condition and online learning have affected Private Universities, especially student behavior. The purpose of this study was to conduct a study of the MARS model to analyze student behavior and its effect on learning effectiveness. The research was conducted on private university students in the city of Semarang, the sample was taken from the population with a purposive sampling method sampling technique as many as 150 students as respondents. The analytical tool used is SPSS with Linear Regression Method. The results showed that the MARS model had a significant influence on student behavior and had a positive and significant effect on learning effectiveness.