Insomnia is a public health problem with many repercussions. It affects a significant proportion of the general population worldwide, but the estimated prevalences in different countries are difficult to compare due to the use of heterogeneous methodologies. The objectives of the study were to compare the prevalence of insomnia in the general population in different sites around the world and to identify sociodemographic and mental health associated factors, using the same tool and within a single study. This multicenter cross-sectional study is based on the Mental Health in the General Population survey (MHPG). It included several sites in France and 12 countries around the world with a representative sampling of the general population. The prevalence of short-term insomnia disorder was estimated by the occurrence within one month of at least one symptom, at a minimum frequency of three per week, with repercussions on everyday life. Out of the 57,298 participants, 11.3% had a diagnosis of short-term insomnia disorder, with significant differences in prevalence between sites, ranging from 2.3% to 25.5%. Insomnia was significantly related to having mood disorders, anxiety disorders, substance use disorders and psychotic disorders. Insomnia was also more common among women, older adults, working participants and those who practice a religion. The prevalence of insomnia was highly variable between sites, but the predictors appeared to be the same everywhere. Insomnia seemed to be more related to the presence of mood and anxiety disorders than a site-specific effect and thus may be a good indicator of mental health.