Importance: The current recommendation is to perform re-resection for select patients with incidentally discovered gallbladder cancer. The optimal time interval for re-resection for both patient selection and long-term survival is not known. Objective: To assess the association of time interval from the initial cholecystectomy to reoperation with overall survival. Design, Setting, and Participants: This cohort studywas conducted from January 1, 2000, to December 31, 2014 at 10 US academic institutions. A total of 207 patients with incidentally discovered gallbladder cancer who underwent reoperation and had available data on the date of their initial cholecystectomy were included. Exposures: Time interval from the initial cholecystectomy to reoperation: group A: less than 4 weeks; group B: 4 to 8 weeks; and group C: greater than 8 weeks. Main Outcomes and Measures: Primary outcomewas overall survival. Results: Of 449 patients with gallbladder cancer, 207 cases (46%) were discovered incidentally and underwent reoperation at 3 different time intervals from the date of the original cholecystectomy: group A: less than 4 weeks (25 patients, 12%); B: 4 to 8 weeks (91 patients, 44%); C: more than 8 weeks (91 patients, 44%). The mean (SD) ages of patients in groups A, B, and C were 65 (9), 64 (11), and 66 (12) years, respectively. All groups were similar for baseline demographics, extent of resection, presence of residual disease, T stage, resection margin status, lymph node involvement, and postoperative complications. Patients who underwent reoperation between 4 and 8 weeks had the longest median overall survival (group B: 40.4 months) compared with those who underwent early (group A: 17.4 months) or late (group C: 22.4 months) reoperation (log-rank P = .03). Group A and C time intervals (vs group B), presence of residual disease, an R2 resection, advanced T stage, and lymph node involvement were associated with decreased overall survival on univariable Cox regression. Only group A (hazard ratio, 2.63; 95%CI, 1.25-5.54) and group C (hazard ratio, 2.07; 95%CI, 1.17-3.66) time intervals (vs group B), R2 resection (hazard ratio, 2.69; 95%CI, 1.27-5.69), and advanced Tstage (hazard ratio, 1.85; 95%CI, 1.11-3.08) persisted on multivariable Cox regression analysis. Conclusions and Relevance: The optimal time interval for re-resection for incidentally discovered gallbladder cancer appears to be between 4 and 8 weeks after the initial cholecystectomy.