The study examined the relationships among environmental attitude, sustainable behavior, and social connectedness, specifically aiming to assess the mediating effect of social connectedness on the relationship between environmental attitude and sustainable behavior among university students at one of the private higher education institutions in Davao City, Philippines. The total sample size was determined using the Raosoft sample size calculator, and participants were selected through stratified random sampling. Survey questionnaires were distributed to 378 students from the College of Accounting Education, College of Architecture and Fine Arts Education, College of Arts and Sciences Education, College of Computing Education, College of Criminal Justice Education, College of Engineering Education, College of Hospitality Education, College of Health Science Education, and College of Teacher Education. Statistical tools, including the mean and Pearson's r, were employed to analyze the results. Findings revealed no significant relationships among environmental attitude, sustainable behavior, and social connectedness, thereby preventing the researchers from performing a mediation analysis. The study, therefore, rejects its theoretical assumption that social connectedness mediates the relationship between environmental attitude and sustainable behavior.