Background: Drug use is an important underlying factor in risky sexual behaviors. Risky sexual behaviors can lead to STIs and HIV/AIDS, especially in women. For better understanding of the relationship between drug use and risky sexual behaviors in women, it is necessary to identify the process of the formation of these behaviors that is a multidimensional process influenced by multiple socio-cultural factors. Therefore, the present study aims to explore the process of risky sexual behaviors formation in women drug users. Methods: This is a grounded theory qualitative study with Corbin and Strauss approach. The participants of the study are women drug users with risky sexual behaviors who, using purposeful sampling method, will be selected from the Counseling and Harm Reduction centers for vulnerable women, the Drug Rehabilitation centers affiliated to the Isfahan University of Medical Sciences, Therapeutic Community Rehabilitation centers, Drop in Centers affiliated to the Welfare Organization, Medium-term Residential centers (women's camps), and Women's Empowerment centers in Isfahan, Iran. Sampling will continue using snowball method and the strategy of maximum variation in terms of the age, occupation, education, duration of the drug use, and type of the drug. During the sampling process, theoretical sampling will gradually replace purposeful sampling, so that sampling will proceed based on the emergence of the theory and for understanding of the concept and, then, the next participants will be selected. Sampling will continue until data saturation is reached. Data will be collected using individual semi-structured in-depth interviews, observation, field notes, and memo writing. Data will be coded as they are collected, and the analysis will be performed at three levels of open, axial, and selective coding and based on the constant comparative analysis. The four criteria of credibility, dependability, transferability and confirmability will be used to ensure the trustworthiness of the data. Discussion: The findings of the present study are expected to provide a better understanding of the process of risky sexual behaviors formation in women drug users. The findings may also lead to the identification of the barriers and factors contributing to the formation of such behaviors and, finally, will promote the reproductive and sexual health of these women. This study can also provide the guide and the ground for designing and conducting further studies in the related areas through using various qualitative and quantitative methods.