Background Unplanned pregnancies continue to be a major public health problem particularly in low-income countries. Their increase the risk of unsafe abortion, maternal morbidity, and mortality. Contraceptive methods play a crucial role in reducing unplanned pregnancies by providing individuals with the means to prevent or delay pregnancy. The recent Rwanda Demographic and Health Survey RDHS (2020) revealed a higher unmet need for family planning among adolescents and young adults compared adults’ women. This study aimed to provide valuable insights into the current status of contraceptive knowledge, attitudes, and practices among young women attending selected health centers in Gasabo district. Methods A cross-sectional study design was employed and quantitative approach was used to collect data from adolescent and young women aged 15 to 24 years who sought routine services at 16 health centers in Gasabo District. The sample size was determined using the Cochran formula, resulting in a sample of 384 participants selected using stratified sampling method. Data were cleaned analyzed using SPSS version 21. Results The results showed that 81.4% of the participants have good knowledge regarding contraceptive methods, while 18.6% have poor knowledge. The respondents generally held a positive attitude towards contraceptive methods (79.4%), Morever, 76.3% exhibit good practice towards the use of contraceptive methods. The Logistic regression showed that young women 20-24 years (AOR = 3.436, 95% CI = 1.007-6.733, p = 0.022), Having more than one child (AOR = 2.461, 95% CI = 1.054-7.246, p = 0.024), coming from higher ubudehe Category (AOR = 1.427, 95% CI = 1.071-3.561, p = 0.035) and receiving more income (AOR = 1.616, 95% CI = 1.025-3.671, p = 0.028) increase the odds of contraceptive methods use. However, being unemployed (AOR = 0.447, 95% CI = 0.09-0.921, p = 0.03) was negatively associated with contraceptive methods use. Conclusion This study highlights the importance of contraceptive methods in reducing unplanned pregnancies. The findings indicate a good level of knowledge, positive attitudes, and satisfactory practices among young women in Gasabo District. However, targeted interventions addressing factors such as age, parity, socioeconomic status, and employment are needed to further promote contraceptive use and minimize unplanned pregnancies.