Background Gender-based violence (GBV) among female sex workers (FSWs) negatively affects their mental wellbeing and sexual and reproductive health and rights. This study aimed to determine the prevalence and associated factors of client-perpetrated GBV among FSWs in post-conflict Gulu district, Northern Uganda. Methods A cross-sectional study was conducted among 300 FSWs aged 18+ years who were operating in Gulu district. Participants were selected using simple random sampling and interviewed between March and June 2020. Pre-tested semi-structured questionnaires were utilized to collect information on socio-demographic and sex-work-related characteristics, alcohol and illicit drug use, HIV status, and exposure to client-perpetrated GBV. Data were entered into EPI INFO 7 and analyzed using logistic regression with the aid of STATA 14.0. Results Sixty one percent (61.0%) of the participants reported client-perpetrated GBV. The most common forms of GBV in this population were economic (58.7%) and emotional (52.0%) violence. Meanwhile, sexual violence (21.0%) was the least common form of GBV among the study participants. At multivariate level; street-based sex work (aOR=9.66, 95%CI: 2.78-33.5), mobile sex work (aOR=3.21, 95%CI: 1.83-5.64), HIV-positive status (aOR=1.90, 95%CI: 1.09-3.31), and low monthly income below 50th percentile { Conclusion Our findings revealed a high prevalence of client-perpetrated GBV driven by street-based sex work, sex work-related mobility, HIV-positive status, and low income. Therefore, interventions to address client-perpetrated GBV should target FSWs who are street-based, HIV-positive, mobile, and with low income. Strengths and limitations of this study ▪Unlike most previous studies among the FSWs that used the non-probability methods of participants’ selection, we utilized a simple random sampling technique to select our sample. Thus, our study participants were representative of the FSWs. ▪However, the information collected may have been influenced by recall bias since we asked FSWs about their personal experience of client-perpetrated GBV. ▪In addition, we implored some sensitive information relating to sex work that might have been difficult to answer which might have resulted into information bias. I, the Submitting Author has the right to grant and does grant on behalf of all authors of the Work (as defined in the below author licence), an exclusive licence and/or a non-exclusive licence for contributions from authors who are: i) UK Crown employees; ii) where BMJ has agreed a CC-BY licence shall apply, and/or iii) in accordance with the terms applicable for US Federal Government officers or employees acting as part of their official duties; on a worldwide, perpetual, irrevocable, royalty-free basis to BMJ Publishing Group Ltd (“BMJ”) its licensees and where the relevant Journal is co-owned by BMJ to the co-owners of the Journal, to publish the Work in this journal and any other BMJ products and to exploit all rights, as set out in our licence. The Submitting Author accepts and understands that any supply made under these terms is made by BMJ to the Submitting Author unless you are acting as an employee on behalf of your employer or a postgraduate student of an affiliated institution which is paying any applicable article publishing charge (“APC”) for Open Access articles. Where the Submitting Author wishes to make the Work available on an Open Access basis (and intends to pay the relevant APC), the terms of reuse of such Open Access shall be governed by a Creative Commons licence – details of these licences and which Creative Commons licence will apply to this Work are set out in our licence referred to above. Other than as permitted in any relevant BMJ Author’s Self Archiving Policies, I confirm this Work has not been accepted for publication elsewhere, is not being considered for publication elsewhere and does not duplicate material already published. I confirm all authors consent to publication of this Work and authorise the granting of this licence.