BACKGROUND: Heavy alcohol use is common in Malawi among people receiving sexually transmitted infections (STI) care and is a critical barrier to the success of HIV prevention and treatment efforts. METHODS: This protocol presents a pilot hybrid type 1 effectiveness-implementation trial evaluating the short-term effectiveness and implementation of a scalable evidence-based intervention (EBI) to reduce alcohol use and provide HIV prevention and treatment counseling for people with heavy drinking receiving STI care in Malawi. We developed a 3-session intervention, Treat4All, that uses motivational interviewing, problem-solving skills, psychoeducation, alcohol refusal, HIV prevention and treatment skills building, and goal setting to reduce alcohol and facilitate engagement in HIV prevention and treatment. We have also integrated HIV prevention content to focus on persistent PrEP use and HIV treatment adherence to improve antiretroviral therapy (ART) adherence and viral suppression. We will conduct a two-arm pilot randomized controlled trial (RCT) in an STI care setting in urban Malawi to compare the preliminary effectiveness and implementation of Treat4All to usual care for decreasing the proportion of heavy drinking days, corroborated with phosphatidylethanol, an alcohol biomarker, and improving HIV outcomes (viral suppression among PWH; PrEP use among those at risk). We will randomly assign 160 people receiving STI care in Lilongwe who report heavy drinking ( = 80 people with HIV; PWH;  = 80 people at high risk of HIV acquisition) to Treat4All or usual care. DISCUSSION: Our study will produce a systematically braided, scalable HIV status-neutral EBI for alcohol reduction and optimization of HIV prevention and treatment behaviors to evaluate in a larger effectiveness-implementation trial. Our study will directly expand alcohol reduction and HIV status-neutral programs for alcohol-impacted populations throughout sub-Saharan Africa and other regions where alcohol contributes to the ongoing HIV epidemic. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT06668363.