Pre-exposure prophylaxis (PrEP) is a highly effective method for preventing HIV acquisition and plays a crucial role in the Ending the HIV Epidemic in the US initiative. However, there are various barriers that hinder the access and uptake of PrEP among Latino sexual minority men (SMM) at individual, interpersonal, and cultural levels. While the significance of cultural factors in designing and implementing HIV prevention programs for Latino populations has been consistently emphasized in the literature and prioritized by the Centers for Disease Control and Prevention, few studies have directly integrated these cultural factors into their programs. Our study aimed to investigate the potential influence of siblings in promoting the utilization of PrEP for HIV prevention, an area that has received limited attention. We conducted interviews with 31 pairs of siblings between December 2020 and January 2021, which were held in either English or Spanish and lasted approximately 45-60 min. The data were analyzed using a deductive thematic content analysis approach. The interviews revealed several key themes and categories, including: (1) Sibling support for coming out; (2) Types of support that siblings provide to each other for behavior change; (3) Sibling support for PrEP; and (4) The impact of the study interview on the quality of the sibling relationships. Our findings indicated that siblings were willing to provide support for PrEP in various ways, ranging from emotional support for brothers who may be concerned about potential rejection to practical support such as transportation or financial assistance. These results have significant implications for the design of HIV prevention interventions for Latinos. Incorporating siblings or other extended family members into these interventions can facilitate communication between siblings and their brothers, ultimately encouraging the use of PrEP or similar prevention methods. By considering the unique dynamics and support systems within Latino communities, researchers can develop more effective strategies to promote HIV prevention and support the well-being of Latino SMM.