Background: A third of people living with HIV (PLHIV) in Western Africa are not diagnosed, hindering progress towards HIV elimination. Scaling-up HIV self-testing (HIVST) among key populations (KP) such as female sex workers (FSW), their clients, and men who have sex with men (MSM), may further curb HIV transmission in this region. Using data from the ATLAS program in Côte d’Ivoire, we projected the potential impact of a national HIVST strategy among KP in the country. Methods: A deterministic model of HIV transmission and different testing modalities among key and lower-risk populations was parameterized following a review of demographic, behavioural, HIV and intervention data of the epidemic in Côte d’Ivoire over time. The model was then calibrated to empirical outcomes, including HIV prevalence, the fractions of PLHIV ever HIV tested, diagnosed, and treated, by risk group. Based on interim ATLAS HIVST programme data among KP in southern Côte d’Ivoire, we assumed that 440,000 HIVST are distributed annually (i.e. 10% of all tests in the country), including 29%, 22%, 32%, and 18% to FSW, their clients, MSM, and lower-risk populations, respectively. We predicted the potential impact of this HIVST strategy on new HIV infections and deaths, and new diagnoses over 10 years. Results: After 10 years, the HIVST strategy is expected to increase the fraction of all PLHIV diagnosed by 18%-points in both FSW (86% vs 69% without HIVST) and MSM (95% vs 77%), resulting in small increases overall (85% vs 83%). Overall, this strategy may avert 10,800 (5,100-24,200) new HIV infections over 10 years; equivalent to one infection averted per 400 HIVST distributed. This corresponds to a relative decrease in new infections of 10% (5-17%), 9% (4-21%), and 32% (23-48%) among FSW, their clients, and MSM, respectively, and 5% (3-10%) overall. However, given the larger population size, two-thirds (63%; 44-78%) of all infections prevented over 10 years were among all lower-risk populations, reflecting the indirect effects of prioritizing KP. HIV mortality among FSW and MSM may be reduced by around 15% over 10 years, vs 4% among FSW clients and 2% overall (i.e. 2700 (1400-5600) total deaths averted). Conclusions and recommendations: A national HIVST strategy may prevent 3-10% of new HIV infections in Côte d’Ivoire, especially among FSW clients and MSM. This would help reduce disparities in HIV burden by reaching key populations and addressing their unmet treatment needs.