OBJECTIVE: To estimate the generalizability of treatment effects observed in a randomized trial of hip fracture surgery implants to a broader population of people undergoing hip surgery in the United Kingdom. STUDY DESIGN AND SETTING: In 2018, the WHiTE-3 trial (n = 958) demonstrated that a modular hemiarthroplasty implant conferred no additional benefit over the traditional monoblock implant for quality of life and length of hospital stay. We compared and weighted the trial sample against two target populations: WHiTE-cohort (n = 2,457) and UK-National Hip Fracture Database (NHFD, n = 190,894), and re-estimate expected treatment effects for the target populations. RESULTS: Despite differences in baseline characteristics of the trial sample and target populations, the re-estimated treatment effects were comparable. For quality of life, the differences between the trial estimate and WHiTE-cohort and NHFD estimates were 0.01 points on the EuroQol (EQ5D). For length of stay, the difference between the trial estimate and WHiTE-cohort was 0.50 days; and the difference between the trial estimate and NHFD estimate was -0.47 days. CONCLUSION: This generalizability analysis of the WHiTE-3 trial found that the inferences from the trial can be generalized to a wider population of individuals in the UK NHFD and the WHiTE-cohort who met the inclusion criteria for WHiTE-3.