This qualitative case study aims to investigate the most common factors that negatively affect adjustment to university and coping strategies used by first-year university students in the adaptation process from the viewpoint of first-year university students. The participants were 25 first-year university students from various faculties at Mersin University. The data were gathered through interviews, which comprised 24 interview questions developed by the researchers. Collected data were content-analyzed following the process of identifying, coding, and categorizing data patterns. The results revealed significant factors that negatively affect the academic, social, personal-emotional, and institutional adjustment of first-year university students. These students' academic adjustment was negatively affected by relationships with faculty and teaching quality, whereas social adjustment was negatively affected by friendship relations, participation in recreational activities, and leisure-time management. In addition, individual factors, such as shyness, fear of failure/disapproval, loneliness, and homesickness, and institutional factors, such as sense of identity and belonging to a university, were perceived as prominent factors affecting students' adjustment. The results also indicated that these students mostly used avoidance coping to deal with challenges in the university adjustment process.