Background: Mangrove ecosystems are critical coastal environments that provide essential ecological services and act as buffers between terrestrial and marine systems. Increasing antibiotic usage in aquaculture and coastal agriculture has led to the dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in these environments. Methods: A narrative search was conducted across PubMed, Scopus, Web of Science, and other databases for studies published up to 2025. Studies were screened according to predefined inclusion criteria focusing on ARGs and ARB in mangrove sediments, water, and associated biota. Data were extracted on ARG prevalence, microbial community composition, detection methods, and environmental factors. Results: Thirty primary studies were identified, with an additional set of candidate studies awaiting verification. ARGs associated with tetracyclines, sulfonamides, β-lactams, and multidrug resistance were prevalent in sediments and aquaculture-influenced mangroves. Metagenomic studies revealed high diversity of ARGs and mobile genetic elements, indicating potential for horizontal gene transfer. Sources of ARG contamination included aquaculture effluents, urban runoff, and agricultural drainage. Conclusion: Mangrove ecosystems act both as reservoirs and buffers for ARGs. Continuous monitoring, sustainable aquaculture practices, and integrated One Health approaches are critical to mitigate the spread of antimicrobial resistance in these sensitive environments.