Surprise out-of-network (OON) bills can represent a considerable cost burden on patients. However, OON billing remains underexplored in elective, outpatient surgery procedures, which have greater latitude for patient choice. We aimed to answer the following questions: (1) What is the prevalence and magnitude of OON charges in hand surgery? (2) What are the sources of OON charges? and (3) What factors are associated with OON charges? We analyzed patient-level data from the Clinformatics Data Mart database. We identified patients undergoing carpal tunnel release, trigger finger release, wrist ganglion removal, de Quervain release, limited palmar fasciectomy, or thumb carpometacarpal arthroplasty at in-network facilities with an in-network primary surgeon. The primary outcome was the proportion of surgical episodes with at least 1 OON charge. Secondary outcomes included the magnitude of potential balance bills (portion of OON bill exclusive of the standardized payment and expected patient cost-sharing), sources of OON charges, and factors associated with OON charges. Of 112,211 elective hand surgery episodes, 8% (9,158) had at least 1 OON charge. OON charges ranged from $1,154 (95% confidence interval, $1,018-$1,289) for wrist ganglion removal to $3,162 (95% confidence interval, $2,902-$3,423) for thumb carpometacarpal arthroplasty. In episodes with OON charges, the major sources of OON charges were anesthesiologists (75% of episodes), durable medical equipment (10% of episodes), and pathologists (9% of episodes). Site of service, geographic region, and health exchange-purchased plans were highly associated with OON charges. Out-of-network billing can represent a substantial cost burden to patients and should be considered in perioperative decision-making in elective hand surgery. Understanding the potential costs related to OON services during a surgical episode, and its drivers, allows surgeons to consider detailed cost discussions during perioperative decision making.