Climate change and global warming are reshaping deep-sea ecosystems, especially impacting harpacticoid copepods that are crucial to deep-sea sediments and dominate meiobenthic communities. Rising ocean temperatures, deoxygenation, and shifts in organic matter deposition are altering their habitats and ecological roles. The Indian Ocean, with its unique monsoon system and expanding oxygen minimum zones (OMZs), is particularly vulnerable. This review examines the distribution and diversity of deep-sea benthic harpacticoids in the Indian Ocean, comparing them with global habitats while considering climate change impacts. We compiled data from the literature on harpacticoid copepods in deep-sea sediments (≥1000 m) from the Indian Ocean and other oceans between 1971 and 2021, focusing on ecology and biodiversity studies. While research on deep-sea harpacticoids varies across habitats, most studies in the Indian Ocean focus on deep-sea basins with polymetallic nodules (PMN). In contrast, areas like trenches, abyssal plains, and seamounts remain largely unexplored in the region, unlike in the Pacific and Atlantic Oceans. The increasing threat of climate change to the Indian Ocean emphasizes the need for further research into its deep-sea biodiversity, as intensified monsoons, declining oxygen levels in OMZs, and warming seas pose challenges for meiofaunal survival. Harpacticoid copepods, due to their sensitivity to environmental changes, are valuable bioindicators of ecosystem health in vulnerable regions. However, significant gaps remain in understanding their adaptability and ecological contributions under climate stress. This review highlights the need for future research to integrate climate change impacts and support the management of anthropogenic activities in sensitive deep-sea regions. Priority should be given to exploring under-studied habitats such as trenches and seamounts in the Indian Ocean to understand better how climate-induced changes affect harpacticoid copepods and their ecosystem roles. Comprehensive studies on the Indian Ocean’s deep-sea ecology will contribute to a broader understanding of biodiversity loss and its long-term consequences for ecosystem function.