Importance Balloon sinus dilation (BSD) is a tool for treating patients with chronic rhinosinusitis or recurrent acute rhinosinusitis. The use of BSD has increased exponentially since its introduction, with concerns for potential misuse. Expert consensus reports that most patients who are candidates for BSD do not need to have all 6 sinuses dilated (bilateral frontal, maxillary, and sphenoid). Objective To determine the percentage of patients who are undergoing 6-sinus BSD, evaluate factors associated with this practice, and explore outlier practice patterns when performing 6-sinus BSD. Design, Setting, and Participants This cross-sectional, retrospective review of a Medicare claims database from January 2022 to December 2023 included otolaryngologists (US Centers for Medicare &amp; Medicaid Services code 04) who performed at least 11 BSDs during the study period, who were defined as high-volume BSD clinicians (&gt;10 BSDs per year). Data were analyzed in July 2024. Main Outcomes and Measures The primary outcome defined before data collection as the percentage of patients billed for 6-sinus BSD. Physician variables were explored for potential association with 6-sinus BSD. Results Of the 522 otolaryngologists (mean [SD] age, 52 [9.3] years), most physicians were male (489 [94%]), practiced in a group setting (428 [82%]), and were in an urban environment (474 [91%]). A total of 21 290 unique BSD procedures were performed, and 12 799 procedures (60%) involved all 6 sinuses. Of the 522 otolaryngologists, 40 (8%) performed 6-sinus BSD in 100% of their BSD procedures, while 54 (10%) performed no 6-sinus BSDs. Practice patterns varied substantially, with 8 physicians (2%) responsible for 10% of 6-sinus BSDs (n = 2152). Conclusions and Relevance The results of this cross-sectional study suggest that the high volume of 6-sinus BSD suggests the potential for overuse of BSD. Substantial variations in care emphasize the need for clear guidelines and indications for multisinus BSD to optimize the utilization and value of BSD.