Introduction. Adolescents with disability are often presumed erroneously to be sexually inactive. Though they have the same need for sexual and reproductive health (SRH) services as nondisabled people, they are often overlooked by sexual and reproductive health programs, interventions, and studies. Objective. To assess determinant factors of sexual and reproductive health service utilization among in-school adolescents with disability in Jimma zone, southwest Ethiopia. Method. Institution-based cross-sectional study design was employed among in-school adolescents with disability in Jimma zone, Ethiopia, from September 21 to November 30, 2021. A total of 454 participants were included in the study by using the multistage sampling technique. Data were collected by using a structured questionnaire through face-to-face interviews. Data were entered into Epi-data version 4.2 and analyzed by using SPSS version 23. Bivariate and multivariable logistic regression analyses at a 95% confidence interval were performed, and a P value < 0.05 was considered statistically significant. Result. 454 study participants were included in this study with a respondent rate of 97.4%. Only 38 (8.4%, 95% CI: 5.7-10.8%) of in-school adolescents utilized SRH information and education service. The majority (265, 49%) of adolescents with disability knew family planning as sexual and reproductive health services which were followed by voluntary counselling and testing for HIV/AIDS (116, 21.4%). Seventy-eight (17.2%, 95% CI: 13.7-20.5%) of in-school adolescents with disability visited nearby health facilities for VCT services. Male sex ( AOR = 2.32 , 95% CI: 1.18-4.57), favourable attitude ( AOR = 3.11 , 95% CI: 1.59-6.07), and history of sexual intercourse ( AOR = 5.34 , 95% CI: 2.05–13.92) were significantly associated with SRH service utilization. Conclusion. The overall sexual and reproductive health service utilization of in-school adolescents with disability was low when compared with other studies. Physical impairment, male sex, ever had sexual intercourse, good knowledge, and favourable attitudes were determinant factors of SRH service utilization among in-school adolescents with disabilities. So, it is recommended that the Jimma zone administration, government, and NGOs should give attention to SRH services.