Primary dysmenorrhea is a highly prevalent gynecological problem and one of the most common causes of school absenteeism among school adolescents. Nearly, half of females with primary dysmenorrhea missed school or work at least once per cycle. Therefore, this study aimed to assess the prevalence of primary dysmenorrhea and its associated factors among female students in Wolaita soddo town high schools. Methods: An institution-based cross-sectional study was conducted among female students at Wolaita soddo town high schools from October 1-30/2021. A total of 733 students were selected using a simple random sampling technique. The data were entered using Epi data version 3.1 and exported to SPSS version 25 for analysis. Binary logistic regression analysis was used. Variables with a p-value of <0.05 in the multivariable logistic regression analysis model were considered statistically significant. Results: The prevalence of primary dysmenorrhea was 70% (95% CI (66.6%, 73.4%)). Factors such as age <18 years (AOR 2.55; 95% CI (1.77, 3.68)), long duration of menstrual flow (AOR 2.72; 95% CI (1.42, 5.17)), irregular menstrual cycle (AOR 2.39; 95% CI (1.68, 3.41)), family history of dysmenorrhea (AOR 2.46; 95% CI (1.67, 3.64)) and skipping breakfast (AOR 1.62; 95% CI (1.13, 2.33)) were associated with primary dysmenorrhea. Conclusion:The prevalence of primary dysmenorrhea was high among high school students in the study area. Being younger age, long menstrual flow duration, irregular monthly menstrual cycle, family history of dysmenorrhea, and skipping breakfast were determinants of primary dysmenorrhea.