Background: Measles remains a major public health challenge in developing countries despite the availability of a safe and effective vaccine. Yemen has experienced frequent outbreaks, particularly among children, due to gaps in vaccination coverage. This study aimed to determine the prevalence, clinical characteristics, and vaccination status of measles cases in Thamar Governorate, Yemen, from January 2020 to December 2022. Method: A retrospective descriptive study was conducted using secondary data from the Measles Surveillance System in Thamar Governorate. Variables included age, sex, vaccination status, case classification, location, and outcome. Data were analyzed using descriptive statistics and presented as frequencies and percentages. Result: A total of 1,890 suspected measles cases were reported. Of these, 217 (11.5%) were laboratory-confirmed, 1,251 (66.2%) were clinically compatible, and 273 (14.4%) were epidemiologically linked. Males constituted 54.1% of the cases. The highest proportion occurred among children aged 1–5 years (61.5%), while infants <6 months accounted for 6.8%. Only 23% of cases were vaccinated, compared to 77% unvaccinated (p < 0.05). The highest annual incidence was recorded in 2022 (79.9% of total cases). The overall case fatality rate was 1.3%. Conclusion: Measles predominantly affected unvaccinated children under five years in Thamar Governorate. The findings highlight low vaccination coverage and the need for intensified immunization programs, enhanced surveillance, and targeted health education to curb transmission and reduce mortality.