Background: Polycystic ovarian syndrome (PCOS), which is characterized by irregular menstrual cycles, is the most common diagnosis given to affected women. For these women, ovulation induction is the usual course of therapy. Objective: To assess the impact of clomiphene citrate, letrozole, and tamoxifen on endometrial thickness in women with unexplained infertility. Subjects and Methods: Female patients with unexplained infertility at Ain Shams University Maternity Hospital participated in the experiment. To stimulate ovulation, they were randomly assigned to receive letrozole, tamoxifen, or clomiphene citrate. Results: The results indicate that there was a substantial statistical difference in basic endometrial thickness (ET) between the three groups, whereas there was not as much of a difference in pre-ovulatory ET. Conclusion: Letrozole and tamoxifen (TMX) should be seen as optional therapies for women who are CC-resistant. In addition, letrozole showed fewer side effects than tamoxifen and performed better than TMX in terms of accelerating the rate of ovulation and pregnancy.