This study estimates the frequency of uninsurance for prescription drugs and cost-related medication nonadherence (CRNA) among lesbian, gay, and bisexual (LGB) persons in Canada, compared with the heterosexual population. Logistic regression was used to quantify associations between sexual orientation, insurance status, and CRNA within the national probability-based Canadian Community Health Survey, 2015-2016. This sample included 98,413 individuals aged 15-80 years, including 2803 LGB individuals. From our sample of Canadians, 22.2% of LGB respondents reported being uninsured for prescription drugs, compared with 20.0% of heterosexual persons (unadjusted odds ratio [UOR] 1.14, 95% confidence interval [CI] 0.97-1.35). LGB individuals had more than twice the odds of reporting CRNA compared with heterosexual individuals (UOR 2.48, 95% CI 1.99-3.10). This disparity was most pronounced among bisexual respondents, who had over three times the odds of reporting CRNA in comparison to heterosexual respondents (UOR 3.45, 95% CI 2.65-4.51). The odds ratio (OR) for CRNA comparing bisexual with heterosexual individuals remained statistically significant after adjustment for race/ethnicity, gender/sex, and age (OR 2.67, 95% CI 1.97-3.61) and was further attenuated with adjustment for partnership status, employment status, income, educational attainment, prescription drug insurance status, general health status, and immigration status (OR 2.09, 95% CI 1.51-2.89). LGB Canadians reported more CRNA but comparable prescription drug insurance frequencies to heterosexual persons. Factors pertaining to medication access (e.g., income, partnership status) and health needs appear to be the most important contributors to disparities.