The objective of the present study was to examine the effectiveness of emotion regulation training on loneliness and distress tolerance of female dormitory students. The research was conducted using a quasi-experimental method with a pre-test and post-test design with a control group. The statistical population of the study included all female students aged 20 to 30 residing in the dormitory of Islamic Azad University, Isfahan (Khorasgan) during the academic year 2023-2024. Out of this population, 40 individuals were selected through convenience sampling and were randomly assigned to two groups: an experimental group (20 individuals) and a control group (20 individuals). The experimental group received eight 90-minute sessions of emotion regulation training using the Gross method. The levels of loneliness and distress tolerance in both groups were measured in the pre-test and post-test using the UCLA Loneliness Scale (Russell et al., 1980) and the Distress Tolerance Scale (Simons & Gaher, 2008). Data analysis was performed using multivariate analysis of covariance (MANCOVA) in SPSS27 software. The findings of the research indicated that emotion regulation training led to a decrease in loneliness scores (F = 61.49, p < 0.01) and an increase in distress tolerance (F = 26.73, p < 0.01) in the experimental group compared to the control group. The results of the present study indicate the effectiveness of emotion regulation training in improving loneliness and increasing distress tolerance of female dormitory students.