Statin therapy plays a central role in decreasing the morbidity and mortality associated with cardiovascular disease. However, prescribed statins are only effective if they are taken by patients on a regular basis, known as medication adherence. The factors that influence patient adherence to statin therapy can be categorized into patient factors, physician factors, and health system factors, often with interactions between the categories. Patient factors include demographics, socioeconomic status, comorbidities, and side effects. Physician factors include the physician's own adherence to applying guideline recommendations, office visits, and their interactions with patients. Health system factors include issues such as cost and access to care. Physicians should be aware of the various elements that may influence a patient's likelihood to take statin medications to improve adherence and provide the best possible patient outcomes.