Introduction <p>A short birth interval is defined as a period of less than 33 months between two consecutive live births. It has a significant impact on population size and the health of mothers and children. This study aimed to assess the prevalence and factors associated with short birth intervals among women of reproductive age in Assosa district, Benishangul Gumuz Regional State.</p> Methods <p>A cross-sectional study design was employed, with data collected from 1520 women aged 15–49 years using structured questionnaires and interview. The data were analyzed using descriptive statistics and accelerated failure time models to identify factors associated with short birth intervals.</p> Results <p>The study found that the prevalence of short birth interval was 55.1%. The results indicated that women’s educational level, the number of children a woman has, age at first marriage, husband’s education level and contraceptive use were significantly associated with short birth intervals.</p> Conclusions <p>Promoting family planning, enhancing maternal and paternal education, conducting awareness campaigns in communities where early marriage is prevalent, and working with religious and community leaders to challenge cultural norms are crucial strategies for reducing the prevalence of short birth intervals and their associated consequences.</p>