<p>Epiphytic algae are microscopic, photosynthetic organisms that colonise the surfaces of aquatic macrophytes and are an essential yet often overlooked component of freshwater habitats. This review paper presents a coherent overview of the diversity, ecological interactions, and environmental influences that determine the composition of the epiphytic algal flora in the mighty Godavari basin. The Godavari River basin is one of the largest and most significant rivers in India and has been experiencing various types of environmental stress. Therefore, it is essential to study algal communities to understand the health of the ecosystem. We review the literature on the species richness and composition of epiphytic algal assemblages, including diatoms, green algae, and cyanobacteria, on various macrophyte hosts and sections of the riverine network. The ecological relationships between epiphytic algae and their macrophyte hosts, including nutrient exchange, light competition, structural support, and protection from desiccation and herbivory, are examined. Additionally, the review examines how abiotic variables, including water quality (e.g., pH, dissolved oxygen, nutrients), flow, seasonality, and anthropogenic pressures (e.g., agricultural runoff, industrial discharges, damming), influence the community structure and dynamics of epiphytic algae in the Godavari. The potential of epiphytic algae as sensitive bioindicators of water quality and ecological change in the river is emphasized. We highlight gaps in current knowledge, especially concerning long-term monitoring data, the effects of emerging pollutants, and the use of molecular techniques in species identification and ecological research. The main aim of this review is to lay a foundation for future studies, conservation, and management of the Godavari River and tropical freshwater ecosystems.</p> Graphical abstract <p></p>