Mangrove ecosystems, which are renowned for their ecological significance and resilience in coastal environments, host a rich diversity of fungi, vital for nutrient cycling, decomposition, and symbiotic relationships with mangrove plants. This chapter delves into the intricate world of mangrove-associated fungi, exploring their taxonomic diversity, ecological roles, adaptations to extreme environments, and influence of various factors on fungal community dynamics. Taxonomic studies have revealed that a plethora of fungal families and genera thrive within mangrove habitats, with notable contributions from taxa such as Dothideomycetes, Pleosporaceae, and Xylariaceae. These fungi play diverse ecological roles, from decomposers to symbionts, shaping the functioning of mangrove ecosystems. This chapter also discusses the factors influencing fungal diversity in mangrove ecosystems, including environmental conditions, unique host associations, geographic location, disturbance regimes, interactions with other organisms, and successional dynamics. Environmental factors such as salinity, pH, temperature, and moisture significantly impact fungal community composition and dynamics, highlighting the adaptability of mangrove fungi to extreme environmental conditions. Moreover, host-specific associations between fungi and mangrove plants contribute to the spatial heterogeneity of fungal communities within mangrove habitats. Furthermore, this chapter explores the biogeography of mangrove-associated fungi, elucidating regional patterns of diversity and shared cosmopolitan species across different geographic regions. Molecular techniques, including DNA sequencing and phylogenetic analysis, have revolutionized our understanding of fungal diversity and evolutionary relationships in mangrove ecosystems, providing valuable insights into the cryptic diversity and phylogenetic affinities of mangrove-associated fungi. Finally, this chapter discusses the ecological roles of mangrove fungi in decomposition, nutrient cycling, and symbiotic interactions with other organisms, highlighting the importance of these fungi in maintaining the health and functioning of mangrove ecosystems.