Background We evaluated whether immigration status modified the association between sex and the quality of primary cardiovascular disease prevention in Ontario, Canada. Methods and Results We used a population‐based administrative database‐derived cohort of community‐dwelling adults (aged ≥40 years) without prior cardiovascular disease residing in Ontario on January 1, 2011. In the preceding 3 years, we evaluated screening for hyperlipidemia and diabetes in those not previously diagnosed; diabetes control (HbA _1c <7%); and medication use to control hypertension, hyperlipidemia, or diabetes in those with previous diagnosis. We calculated the absolute prevalence difference (APD) between women and men for each metric stratified by immigration status and then determined the difference‐in‐differences for immigrants compared with long‐term residents. Our sample included 5.3 million adults (19% immigrants), with receipt of each metric ranging from 55% to 90%. Among immigrants, women were more likely than men to be screened for hyperlipidemia (APD, 10.8%; 95% CI, 10.5–11.2) and diabetes (APD, 11.5%; 95% CI, 11.1–11.8) and to be treated with medications for hypertension (APD, 3.5%; 95% CI, 2.4–4.5), diabetes (APD, 2.1%; 95% CI, 0.7–3.6) and hyperlipidemia (APD, 1.8%; 95% CI, 0.5–3.1). Among long‐term residents, findings were similar except poorer medication use for diabetes (APD, −2.8%; 95% CI, −3.4 to −2.2) and hyperlipidemia (APD, −3.5%; 95% CI, −4.0 to −3.0]) in women compared with men. Conclusions The overall quality of primary preventive care can be improved for all adults, and future research should evaluate the impact of observed equal or better care in women than men, irrespective of immigration status, on cardiovascular disease incidence.