Abstract Context Craniopharyngiomas, while benign, have the highest morbidity of all nonmalignant sellar tumors. Studies on weight and metabolic outcomes in adult-onset craniopharyngioma (AOCP) remain sparse. Objective To examine postsurgical weight and metabolic outcomes in AOCP and to identify any clinical predictors of weight gain. Methods Retrospective chart review of patients with AOCP who underwent surgery between January 2014 and May 2019 in a single pituitary center. The study included 45 patients with AOCP with a minimum follow-up of 3 months. Median follow-up time was 26 months (interquartile range [IQR] 10-44). Main outcome measures were the changes in weight/body mass index (BMI), metabolic comorbidities, and pituitary deficiencies between preoperative and last follow-up. Results Both weight and BMI were higher at last follow-up, with a mean increase of 3.4 kg for weight (P = .015) and 1.15 kg/m2 for BMI (P = .0095). Median % weight change was 2.7% (IQR –1.1%, 8.8%). Obesity rate increased from 37.8% at baseline to 55.6% at last follow-up. One-third of patients had ~15% median weight gain. The prevalence of metabolic comorbidities at last follow-up was not different from baseline. Pituitary deficiencies increased postoperatively, with 58% of patients having ≥3 hormonal deficiencies. Preoperative BMI was inversely associated with postoperative weight gain, which remained significant after adjusting for age, sex, race, tumor, and treatment characteristics. Patients with ≥3 hormonal deficiencies at last follow-up also had higher postoperative weight gain. Conclusion In this AOCP cohort, those with a lower BMI at the preoperative visit had higher postoperative weight gain. Our finding may help physicians better counsel patients and provide anticipatory guidance on postoperative expectations and management.