Abnormal liver tests are one of the most common challenges in the primary care setting. Primary care practitioners order these tests for numerous reasons, including investigating abdominal signs and symptoms or suspected alcohol-use disorder, or to determine medication adverse effects. Evaluation should be guided by both the clinical presentation and the pattern of injury. In this article, we will focus on the epidemiology, pathophysiology, clinical presentation, diagnostic work-up, and management of elevated liver enzymes, with an emphasis on the most common causes of abnormal liver testing.