Purpose To compare the efficacy and cosmetic outcome of limited posterior lamellar advancement compared to anterior lamellar marginal Z-plasty to manage segmental trichiasis of the lateral part of the upper lid. Patients and methods This retrospective study included patients with focal trichiasis limited to the lateral part of the upper lid who were treated by either the limited posterior lamellar advancement (group I) or anterior lamellar marginal Z-plasty (group II) at a tertiary care center in the period between October 2020 and May 2024. Recurrence (primary outcome measure) was defined as one or more lashes touching the eye, causing foreign body sensation and symptomatic dissatisfaction. Cosmetic satisfaction and intraoperative or postoperative complications were considered secondary outcome measures. Results A significant difference between the groups regarding the recurrence rate was observed, with group II having a higher recurrence rate compared to group I after 3 months (42.86 and 13.04%), with a P value equal to 0.027. The cosmetic results were better in group II during the first month postoperatively. Surgery duration was shorter in group I than in group II. Conclusion Limited posterior lamellar advancement is a safe and effective technique for the management of segmental trichiasis of the lateral part of the upper lid, with a lower recurrence rate and a final acceptable cosmetic outcome compared to anterior lamellar marginal Z-plasty.