Low-dose radiation is highly effective for localized mycosis fungoides (MF), but optimal fractionation remains uncertain. This retrospective study compared outcomes between single-fraction 8 Gy and split-fraction 4 Gy × 2 regimens. Both treatments produced high response rates with no significant differences in recurrence, need for retreatment, or time to subsequent therapy. No grade ≥2 toxicities were observed, underscoring excellent tolerability. Although Cox modeling suggested a nonsignificant trend toward higher relapse hazard in the 8 Gy group, overall efficacy was comparable. Demographic and lesion-specific characteristics did not influence outcomes. Given similar therapeutic performance and the practical advantage of reduced visits, single-fraction therapy may be especially beneficial for patients with geographic or mobility barriers. Larger, multicenter prospective studies are needed to validate equivalence and assess long-term durability.