Mangrove forests are recognized as ancient, highly productive, and thriving ecosystems. These environments are prevalent in tropical and subtropical coastal areas, serving as sanctuaries that harbor diverse communities of plants, fish, and micro- and macro-aquatic organisms. These environments possess distinctive physicochemical attributes, rendering them among the most challenging ecosystems. They are characterized by high salinity, tidal fluctuations, ongoing water influx and efflux, desiccation, acidic pH, and anaerobic conditions. Also, the mangrove ecosystem is characterized by a distinct soil composition that diverges from typical terrestrial soils. The mangrove soil is known to have a high mineral content, comprising a combination of silt, clay, and sand particles. The mangrove soil, enriched with decomposed plant material, exhibits elevated organic content. The continuous water inundation generates an anaerobic milieu coupled with acid sulfate formation, resulting in acidic soil pH and rendering mangrove substrates one of the most extreme environmental settings. Despite the challenging environmental conditions, the mangroves harbor a diverse community of microbes, encompassing bacteria, particularly actinobacteria, fungi, archaea, protists, and algae. These microbes play pivotal roles in the ecosystem’s decomposition, nitrification, and denitrification processes. Commonly referred to as extremophilic microbes, they possess the remarkable ability to withstand harsh environmental stressors and significantly contribute to the maintenance and preservation of the mangrove ecosystem. Among these, the genus Actinobacteria has emerged as a subject of considerable interest owing to its distinctive adaptive capabilities, resilience in harsh environments, and its relatively uncommon prevalence, which collectively underscore the value of investigating and elucidating the diversity within this microbial group. This chapter primarily examines the diverse distribution of mangroves across India, with a particular focus on the mangrove-associated actinobacteria species. It highlights their presence, abundance, and diversity among various mangrove ecosystems in India, as well as the production of their novel secondary metabolites, which hold significant biotechnological potential.