Objective This retrospective cohort study aimed to identify reasons and risk factors associated with 30-day readmission after otolaryngology-head and neck surgery and propose preventive measures. Design The study was conducted at a large single academic tertiary care center in China, analyzing cases of inpatient otolaryngology-head and neck surgery from August 2019 to December 2021. Setting The study was conducted in a large tertiary-care hospital in China. Participants The study included adult patients who underwent otolaryngology-head and neck surgery and experienced 30-day readmissions. Main outcome measures The main outcome measured was the analysis of 30-day readmissions for adult patients after otolaryngology-head and neck surgery. Results A total of 7,608 otolaryngology-head and neck surgery patients were identified, with 0.85% and 0.84% experiencing unplanned and planned readmissions within 30 days, respectively. Patients with unplanned readmissions were older and had a longer length of stay compared to those with planned readmissions and those without readmissions. Old age and length of stay were identified as risk factors for unplanned readmission. The most common reasons for unplanned and planned readmissions were surgical complications and surgical cancellations, respectively. Conclusions Analyzing the causes and risk factors for 30-day readmissions after otolaryngology-head and neck surgery can guide perioperative planning and help prevent readmissions, leading to improved patient outcomes.