Objectives: Excessive alcohol consumption is a major public health concern. Protective behavioral strategies (PBS) are widely incorporated into alcohol interventions, but their effectiveness and role as mechanisms of behavior change remain unclear. This systematic review and meta-analysis evaluated the effects of PBS-based interventions on alcohol consumption, alcohol-related harms, and PBS use. Methods: PubMed, Embase, Scopus, CINAHL, and ProQuest were searched from inception to December 2025 for randomized controlled trials (RCTs) of adults (≥18 years) delivering PBS as an active intervention component. Random-effects meta-analyses using Hedges' g examined alcohol quantity, drinking frequency, alcohol-related problems, and PBS use. Results: Fifteen RCTs were included, predominantly involving young adults attending U.S. universities. PBS interventions increased protective strategy use (g=0.23, p=0.005 after outlier removal), but alcohol effects were modest: no change in quantity (g=− 0.05, p=0.162), small reduction in frequency (g=− 0.09, p=0.014), and marginal reduction in problems (g=− 0.07, p=0.052; significant in sensitivity analysis). Subgroup findings suggested greater effects at longer follow-up and when PBS was incorporated into multi-component interventions. Evidence supporting PBS as a mechanism of change was limited and inconsistent. Conclusions: PBS-based interventions produce modest, context-dependent effects on alcohol outcomes. Most evidence comes from young U.S. university students, underscoring the need for studies in more diverse adult populations and further mechanistic research.