Dual-method use is the most reliable form of protection against unintended pregnancies and HIV/STIs. Although dual-method use remains uncommon among women in stable relationships, some women do practice it. In this study, we explored the barriers that make dual-method use rare and the behaviors of women who practice dual-method use using a positive deviance framework in Uganda. We screened 150 women using highly effective contraceptives at five health facilities. We identified nine women who practiced dual-method use and 141 women who did not. In a qualitative study, we conducted in-depth interviews with all nine women practicing dual-method use and 10 women randomly selected out of the 141 who did not. We performed a thematic analysis using the positive deviance framework. Regardless of practicing dual-method use or not, women faced perceived barriers against dual-method use, such as partner’s objection, distrust, shyness about introducing condoms into marital relationships, and limited access to condoms. However, women practicing dual-method use had higher levels of risk perception about unintended pregnancies and HIV/STIs. They also engaged in unique behaviors, such as influencing their partners’ condom use by initiating discussions, educating their partners on sexual risks and condom use, and obtaining condoms by themselves. These findings will be useful in developing effective community-led and peer-based interventions promoting dual-method use to reduce the dual burden of unintended pregnancies and HIV/STIs among women in Uganda.