Background: Adherence to guideline-recommended statin recommendations in the United States is suboptimal. Patients' likelihood to be treated according to guidelines may vary by the practice in which they are treated. Methods: Variation in the use of statin therapy in 5445 patients, with known or at high risk for atherosclerotic cardiovascular disease (ASCVD) and meeting a statin treatment indication, was examined across 74 US Patient and Provider Assessment of Lipid Management (PALM) Registry clinics. Multivariable generalized linear mixed modeling was used to determine the median odds ratio (MOR) for statin use and 2013 American College of Cardiology/American Heart Association guideline-recommended statin intensity by practice. MOR quantifies between-practice variation by comparing the odds of receiving guideline-recommended statin treatment in a patient from a randomly selected practice with a similar patient from another random practice. Risk-adjusted low-density lipoprotein cholesterol (LDL-C) control (<100 and <70 mg/dL) was compared among practice tertiles based on percentage of eligible patients receiving recommended statin intensity. Results: Among 74 practices (43.2% cardiology) comprised of 300 healthcare providers enrolling 5445 patients (56.2% with ASCVD), statin use at the guideline-recommended intensity at practices varied widely (12.7–71.4%; adjusted MOR 1.45, 95% confidence interval [CI] 1.35–1.64). Results were consistent when evaluated for any statin use overall (adjusted MOR 1.75, 95% CI 1.48–1.99) and when stratified by primary versus secondary prevention patients. Relative to practices with lowest or mid-tertile statin use of statins, highest tertile clinics were more frequently cardiology practices (68.0% vs 48.0% vs 12.5%, P < .001). Compared with lowest tertile clinics, patients at highest tertile clinics were more likely to achieve LDL-C <70 mg/dL (adjusted odds ratio [OR] 1.49, 95% CI 1.08–2.04) and <100 mg/dL (adjusted OR 1.78, 95% CI 1.41–2.25). Conclusions: US clinics varied widely in their adherence to guideline recommendations for statin therapy, which contributed to significant differences in LDL-C levels.