Objective To determine whether there is a statistically significant difference in the surgical outcome of everting sutures (ES) alone versus everting sutures with a lateral tarsal strip (ES+LTS) in the treatment of involutional entropion. Design Prospective randomized comparative trial. Participants Sixty-three patients with primary involutional lower eyelid entropion were enrolled in the study. The age range was 54 to 94 years, with a mean age of 77 years. Baseline characteristics of the comparative groups were similar. Methods Patients requiring primary surgical repair for involutional entropion were selected, and those providing informed consent were randomized for surgery. Thirty-six patients were randomized to ES alone, and 27 patients were randomized to ES+LTS. Patients were evaluated at 3 weeks and 6, 12, and 18 months postoperatively. Main Outcome Measures Successful surgery was defined as a normal eyelid position at rest and inability to induce entropion on tetracaine provocation testing at or before the 18-month follow-up visit. Results Eight patients were lost to follow-up (7 had ES alone). Of the 55 patients with complete follow-up data, there were 6 failed procedures in the patients who underwent ES alone and no failed procedures in the patients who underwent ES+LTS ( P = 0.02). Conclusions These data provide strong evidence that success rates at 18 months are higher in patients treated with ES+LTS procedure compared with ES alone. Financial Disclosure(s) The authors have no proprietary or commercial interest in any materials discussed in this article.