Background Melasma is a common pigmentary disorder that is often difficult to treat. Tranexamic acid (TA) has emerged as a promising treatment for melasma; however, few controlled studies exist. Objective To determine the efficacy of oral TA in patients with moderate-to-severe melasma. Methods Patients with moderate-to-severe melasma were treated with 250 mg of TA or placebo capsules twice daily for 3 months and sunscreen followed by 3 months of treatment with sunscreen only. The primary outcome measure was the modified Melasma Area and Severity Index (mMASI) score. Results A total of 44 patients were enrolled and 39 completed the study. At 3 months, there was a 49% reduction in mMASI score in the TA group versus 18% in the control group. Patients with severe melasma improved more than those with moderate melasma. Three months after treatment was stopped, there was a 26% reduction in mMASI score in the TA group compared with the baseline visit versus a 19% reduction in the placebo arm. No serious adverse events were noted in either group. Limitations Single-center study enrolling predominantly Hispanic women. Conclusions Oral TA appears to be an effective treatment for moderate-to-severe melasma with minimal side effects. Melasma is a common pigmentary disorder that is often difficult to treat. Tranexamic acid (TA) has emerged as a promising treatment for melasma; however, few controlled studies exist. To determine the efficacy of oral TA in patients with moderate-to-severe melasma. Patients with moderate-to-severe melasma were treated with 250 mg of TA or placebo capsules twice daily for 3 months and sunscreen followed by 3 months of treatment with sunscreen only. The primary outcome measure was the modified Melasma Area and Severity Index (mMASI) score. A total of 44 patients were enrolled and 39 completed the study. At 3 months, there was a 49% reduction in mMASI score in the TA group versus 18% in the control group. Patients with severe melasma improved more than those with moderate melasma. Three months after treatment was stopped, there was a 26% reduction in mMASI score in the TA group compared with the baseline visit versus a 19% reduction in the placebo arm. No serious adverse events were noted in either group. Single-center study enrolling predominantly Hispanic women. Oral TA appears to be an effective treatment for moderate-to-severe melasma with minimal side effects.