Background The long-term psychological effects of COVID-19 on dental students are unclear. The aim of this cross-sectional online study was to investigate the psychological effects of the COVID-19 pandemic on dental students. Method The Quality of Life Scale (WHOQOL-BREF) was sent to all dental students through Google Forms to evaluate their quality of life (QoL), and the DASS-21 scale was used to evaluate their psychosocial status due to distance learning during the COVID-19 pandemic. The answers were analyzed both on the basis of year of education and type of education (online versus classroom learning). One-way ANOVA was used for comparison of students in the different years of education; post hoc LSD test was used for pairwise comparisons. Sample t-test was used to compare the two groups separated as classroom/face-to-face learning and distance/online learning. Result The questionnaire was completed by 580 students with a response rate of 87.74%. According to the QoL scale results, there was no significant difference between the groups regarding general health, physical health, and psychology, both between different years and learning methods (p > 0.05). According to the results of the DASS-21 scale, anxiety and depression in the 3rd year students were significantly higher than the other years. The stress level of the 2nd year students was statistically significantly different from the other years (p < 0.05). Evaluation of anxiety, stress and the QoL showed an overall detrimental effect of distance learning on the dental students, although the evaluation did not reach statistical significance. Conclusion Anxiety, stress and factors affecting the quality of life negatively affected dental students who received online/distance learning, although the difference did not reach statistical significance when compared to students who received in-classroom learning.