Latino adults, especially immigrants without citizenship (i.e., noncitizens), experience considerable barriers to health care, including medications. Inequitable access to medications, especially statins, may exacerbate disparities in cardiovascular disease. Despite this, little is known about medication nonadherence in Latino neighborhoods, especially those with large noncitizen populations. To estimate nonadherence to statins in Latino neighborhoods and evaluate differences on the basis of their noncitizen population. We conducted a retrospective cohort study among 48,161 adults who lived in predominately Latino neighborhoods in New York City, Los Angeles, and Chicago and who initiated statin therapy from January 2012 to December 2015 using IQVIA LifeLink. Statin nonadherence was defined as a proportion of days covered amounting to less than 80% over 12 months. We focused on differences between neighborhoods with high noncitizen concentrations (areas where noncitizens are at least 35% of the adult population) and other Latino neighborhoods. We examined associations using logistic regressions adjusted for individual (e.g., payment method) and neighborhood characteristics (e.g., poverty). Individuals living in neighborhoods with high noncitizen concentrations were more nonadherent to statins than those in Latino neighborhoods with fewer noncitizens (75.0% vs. 70.0%, adjusted odds ratio [aOR] 1.18, [95% CI 1.06-1.33]). These disparities were worse in New York City (77.7% vs. 69.1%, aOR 1.37, [95% CI 1.23-1.53]) and Chicago (76.1% vs. 68.8%, aOR 1.38, [95% CI 1.14-1.67]) than in Los Angeles (73.8% vs. 71.3%, aOR 1.10, [95% CI 1.01-1.20]). Neighborhoods with large noncitizen populations have much higher rates of statin nonadherence than Latino neighborhoods with fewer noncitizens. These disparities were least pronounced in Los Angeles, where the county provides health care to all uninsured residents, including noncitizens without documentation to reside in the United States. Efforts to improve medication access in Latino neighborhoods should be multifocal and start by implementing state and local health care options for low-income residents, regardless of citizenship status.