Importance: Transoral endoscopic head and neck surgery now plays an important role in the multidisciplinary management of oropharyngeal carcinoma. Previous generations of robotic surgical systems used a multiport system with a rigid stereo-endoscope and 2 wristed instruments that facilitated transoral robotic surgery. Objective: To evaluate a new single-port robotic surgical system in head and neck surgery prospectively through concurrent nonrandomized clinical trials. Design, Setting, and Participants: Two prospective clinical trials were conducted from December 16, 2016, to December 26, 2017, to assess the safety, feasibility, and performance of a flexible single-port robotic surgical system in 4 institutions, including 3 in the United States and 1 in Hong Kong. A total of 47 patients with tumors of the oropharynx were enrolled and underwent surgery. All patients were classified as having American Society of Anesthesiologists class I to III status and Eastern Cooperative Oncology Group status 0 to 1. An initial cohort of 7 patients underwent staging and endoscopic procedures for benign disease. The remaining 40 patients all had malignant tumors of the oropharynx. Main Outcomes and Measures: Safety was measured by the incidence of device-related serious adverse events. Feasibility and performance were measured by the conversion rate from the use of the single-port robotic surgical system to either open surgery or the use of any other transoral technology required to complete the planned procedure. Secondary end points of swallowing function and surgical margins were also measured. Results: All 47 patients (8 women and 39 men; mean [SD] age, 61  years) safely underwent transoral resection with the single-port robotic surgical system without conversion to open surgery, laser surgery, or multiport robotic surgery. There were no intraoperative complications or device-related serious adverse events. Mean (SD) estimated intraoperative blood loss per procedure was 15.4 (23.9) mL; no patients received a transfusion. Two patients underwent a planned tracheotomy owing to medical comorbidity (previous chemoradiotherapy; obesity and severe sleep apnea). Two patients (4%) had grade III or IV postoperative hemorrhage, requiring a return to the operating room; however, both patients had medical comorbidities requiring the use of antithrombotic medication. The incidence of positive margins for patients with oropharyngeal malignancy was 3% (1 of 40). Within 30 days, 45 patients (96%) were eating by mouth and without the need for a percutaneous endoscopic gastrostomy tube. Conclusions and Relevance: This study describes the results of phase 2 clinical testing of a next-generation, robotic surgical system using a single-port architecture. The use of the device appears to be feasible, safe, and effective for transoral robotic surgery of oropharyngeal tumors. Trial Registration: ClinicalTrials.gov identifiers: NCT03010813 and NCT03049280.