This study is an investigative study to determine the degree of anxiety-attachment, self-esteem, and loneliness of university students, to identify the relationship between these variables, and to explore the degree of influence on loneliness. The subjects of this study were 235 University students. The collected data were analyzed using the SPSS/WIN 26.0 program. The anxiety attachment average was 54.84 (18.00 to 109.00), the self-esteem average was 31.75 (11.00 to 40.00), and the loneliness scored an average 38.37 (20.00 to 72.00). In Model 1, it was found that the personal characteristics did not statistically significantly explain the loneliness of the subjects. In Model 2, psychological characteristics were added to show 58.5% of explanatory power, and anxiety-attachment (β=.24, p<.001), self-esteem (β=-.62, p<.001) was found to be an important influencing factor explaining loneliness. In conclusion, it is believed that it is possible to reduce the loneliness of research subjects in early adulthood by studying ways to increase self-esteem of university students.