Overuse of medical care is an increasingly recognized problem in clinical medicine. To identify and highlight original research articles published in 2015 that are most likely to reduce overuse of medical care, organized into 3 categories: overuse of testing, overtreatment, and questionable use of services. The articles were reviewed and interpreted for their importance to clinical medicine. A structured review of English-language articles on PubMed published in 2015 and review of tables of contents of relevant journals to identify potential articles that related to medical overuse in adults. Between January 1, 2015, and December 31, 2015, we reviewed 1445 articles, of which 821 addressed overuse of medical care. Of these, 112 were deemed most relevant based on their originality, methodologic quality, and number of patients potentially affected. The 10 most influential articles were selected by consensus using the same criteria. Findings included a doubling of specialty referrals and advanced imaging for simple headache (from 6.7% in 2000 to 13.9% in 2010); unnecessary hospital admission for low-risk syncope, often leading to adverse events; and overly frequent colonoscopy screening for 34% of patients. Overtreatment was common in the following areas: 1 in 4 patients with atrial fibrillation at low risk for thromboembolism received anticoagulation; 94% of testosterone replacement therapy was administered off guideline recommendations; 91% of patients resumed taking opioids after overdose; and 61% of patients with diabetes were treated to potentially harmfully low hemoglobin A1c levels (<7%). Findings also identified medical practices to question, including questionable use of treatment of acute low-back pain with cyclobenzaprine and oxycodone/acetaminophen; of testing for Clostridium difficile with molecular assays; and serial follow-up of benign thyroid nodules. The number of articles on overuse of medical care nearly doubled from 2014 to 2015. The present review promotes reflection on the top 10 articles and may lead to questioning other non-evidence-based practices.