OBJECTIVE Frailty is a known predictor of adverse outcomes in pituitary surgery, yet its impact regarding craniopharyngioma remains unclear. The authors assessed preoperative frailty, measured by the 11-factor modified frailty index (mFI-11), and its association with perioperative morbidity among adult patients undergoing craniopharyngioma surgery. METHODS Using the Registry for Adenomas of the Pituitary and Related Disorders (RAPID) database, the authors performed a retrospective cohort study of the records of patients ≥ 18 years of age who underwent craniopharyngioma surgery between June 2007 and November 2024. Patients were stratified into the following categories according to their numeric mFI-11 score: fit (scores 0 and 1), managing well (scores 2 and 3), and mildly frail (scores 4–6). Primary outcomes included hospital length of stay (LOS) and discharge disposition. Secondary outcomes included 90-day readmission, surgical outcomes, and complications. Multivariable analyses were performed to identify independent predictors of hospital LOS and non-home discharge, adjusting for age, surgeon experience, American Society of Anesthesiologists class, complications, and surgical approach. RESULTS Among 278 patients (221 fit, 43 managing well, 14 mildly frail), higher-frailty patients were older (mean age 47.8 ± 16.1 years in fit vs 60.1 ± 12.5 years in managing well vs 67.6 ± 8 years in mildly frail, p < 0.001) and more likely to present urgently (24.2% vs 36.4% vs 78.6%, p = 0.001). Gross-total resection was achieved less frequently in frail patients (44.8% vs 24.3% vs 23.1%, p = 0.030). Overall complication rates were similar; however, increasing frailty was associated with higher rates of postoperative mortality (0% vs 2.8% [1/36] vs 7.7% [1/13], p = 0.018), pneumonia (0.5% [1/195] vs 2.8% [1/36] vs 15.4% [2/13], p = 0.006), and reintubation (2.6% [5/195] vs 2.8% [1/36] vs 30.8% [4/13], p = 0.002). Higher frailty was associated with a stepwise rise in median [IQR] LOS (5 [3–8] days vs 7 [4–12] days vs 13 [6.5–21.8] days, p < 0.001) and remained an independent predictor of extended LOS on multivariable analysis (β = 1.729 per point, p = 0.006). Rates of non-home discharge showed a similar pattern (9.2% vs 30.0% vs 64.3%, p < 0.001), with frailty independently predicting non-home discharge (OR 2.352, 95% CI 1.527–3.822). Unplanned 90-day readmission rates were significantly higher in the mildly frail cohorts (22.5% vs 45.7% vs 53.8%, p = 0.002). CONCLUSIONS The mFI-11 scores independently predicted perioperative morbidity following craniopharyngioma resection. Incorporating frailty screening into preoperative screening may improve risk stratification, family and patient counseling, and discharge planning.