Objective: This study aimed to study the comorbidity of common mental disorders (CMDs) and cancer, and the mental health treatment gap among community residents with active cancer, cancer survivors and cancer-free respondents in 13 high-income and 11 low-middle-income countries. Methods Data were derived from the World Mental Health Surveys (N = 66,387; n = 357 active cancer, n = 1373 cancer survivors, n = 64,657 cancer-free respondents). The World Health Organization/Composite International Diagnostic Interview was used in all surveys to estimate CMDs prevalence rates. Respondents were also asked about mental health service utilization in the preceding 12 months. Cancer status was ascertained by self-report of physician's diagnosis. Results Twelve-month prevalence rates of CMDs were higher among active cancer (18.4%, SE = 2.1) than cancer-free respondents (13.3%, SE = 0.2) adjusted for sociodemographic confounders and other lifetime chronic conditions (adjusted odds ratio (AOR) = 1.44, 95% CI 1.05-1.97). CMD rates among cancer survivors (14.6%, SE = 0.9) compared with cancer-free respondents did not differ significantly (AOR = 0.95, 95% CI 0.82-1.11). Similar patterns characterized high-income and low-middle-income countries. Of respondents with active cancer who had CMD in the preceding 12 months, 59% sought services for mental health problems (SE = 5.3). The pattern of service utilization among people with CMDs by cancer status (highest among persons with active cancer, lower among survivors and lowest among cancer-free respondents) was similar in high-income (64.0%, SE = 6.0; 41.2%, SE = 3.0; 35.6%, SE = 0.6) and low-middle-income countries (46.4%, SE = 11.0; 22.5%, SE = 9.1; 17.4%, SE = 0.7). Conclusions Community respondents with active cancer have higher CMD rates and high treatment gap. Comprehensive cancer care should consider both factors.