Background <p>Frailty is a state of physiological vulnerability rendering patients susceptible to adverse perioperative outcomes after neurosurgery. The effect of frailty on surgical success and complication rates in patients undergoing transsphenoidal pituitary surgery is unclear.</p> Methods <p>A systematic review of the literature was performed in accordance with the PRISMA statement. Studies that utilised validated metrics to report the effect of frailty on pituitary surgery were included.</p> Results <p>A total of 13 studies were included, comprising 124,989 patients. Frailty was exclusively assessed with cumulative deficit metrics, however there was significant heterogeneity in patient population, frailty definitions and assessment, and outcomes. Frail patients undergoing transsphenoidal surgery experienced higher rates of medical complications, resulting in longer hospital stays, greater hospitalisation costs, higher rates of unplanned readmission, more discharges to a destination other than home, and increased mortality. These outcomes directly correlated with increasing degrees of frailty. Surgical outcomes were not affected by frailty, with similar rates of biochemical remission, visual recovery, and improvement in quality of life.</p> Conclusion <p>Frailty is seen in a minority of patients undergoing pituitary surgery, but is an important indicator of perioperative risk. Frailty assessment should not be used as a reason to withhold surgery, but rather to predict and mitigate perioperative complications to improve outcomes in pituitary surgery.</p>