Poor sleep quality is associated with decreased brain health, such as fatigue, low quality of life, and risk of neurological and psychiatric comorbidities. Until now, no testing instruments for an accurate assessment of sleep quality for use in the general population have been rigorously translated and validated in Mongolia. We aimed to determine the psychometric properties of the globally recognized screening tool and sleep quality in the general population of Mongolia. In this cross-sectional study, participants were randomly selected between August and October 2020, from 64 sites in 8 urban, and 9 rural areas in Mongolia. Of the total 1152 participants (mean age, SD=42.66±12.6, range: 18 and 65) 76% were women. An overall Cronbach’s α was 0.69. Both EFA and CFA indicated a two-factor solution. The PSQI total score was positively correlated with anxiety and depression. The PSQI total score (p values < 0.01) was negatively correlated with the mean scores of all domains of WHOQOL-BREF. The mean PSQI total score was 5.67±3.4 and 43% of the participants were classified as poor sleepers by a global cut-off point of 5. The Mongolian version of the PSQI demonstrated a reliable and valid tool for screening sleep quality among the Mongolian general population. The results suggest that the prevalence rate of poor sleep quality was 43% using PSQI global cut-off point.