Long-acting injectable (LAI) formulations of antiretrovirals (ARVs) as pre-exposure prophylaxis (PrEP) could be an attractive alternative for men who have sex with men (MSM) who are interested in ARV-based biomedical prevention but will not use a daily pill. This study investigated interest in LAI-PrEP in a cohort of MSM in China and characterized how MSM willing to use only injectable PrEP differed from MSM who would use PrEP regardless of modality or not at all. Demographic, behavioral, and risk perception measures were collected and associations investigated. A licensed LAI-PrEP agent would increase the proportion interested in PrEP by 24.5% over oral PrEP alone. Combining interest in oral and injectable PrEP, 78.5% of the sample could be covered if reported interest in PrEP translated into actual uptake. Partnership factors differentiated those who would be willing to use only LAI-PrEP versus any PrEP modality, while higher self-perception of risk was associated with interest in LAI-PrEP versus no PrEP. The addition of a second PrEP modality could yield increased population coverage of PrEP. Social and behavioral research should be undertaken in parallel with clinical development of injectable PrEP agents to identify characteristics of those who are not interested in oral PrEP but would take advantage of ARV-based prevention with the introduction of an injectable product.