Antiretroviral pre-exposure prophylaxis (PrEP) to prevent HIV transmission was first approved by the US Food and Drug Administration in 2012. Despite correlations of decreases in new HIV infections being greatest where PrEP has been deployed, the uptake of PrEP is lagging, particularly among populations with disproportionate HIV burden. This narrative review seeks to identify individual and systemic barriers to PrEP usage in the USA. A comprehensive search of recent literature uncovered a complex array of structural, social, clinical, and behavioral barriers, including knowledge/awareness of PrEP, perception of HIV risk, stigma from healthcare providers or family/partners/friends, distrust of healthcare providers/systems, access to PrEP, costs of PrEP, and concerns around PrEP side effects/medication interactions. Importantly, these barriers may have different effects on specific populations at risk. The full potential of PrEP for HIV prevention will not be realized until these issues are addressed. Strategies to achieve this goal should include educational interventions, innovative approaches to delivery of HIV care, financial support, and destigmatization of PrEP and PrEP users. Until then, PrEP uptake will continue to be suboptimal, particularly among those who need it most.