Freshwater mussels (Order Unionoida) globally occupy rivers and lakes ranging from intermittent to perennial, providing key services to humans and ecosystems including water filtration, nutrient cycling and provision of food, materials and cultural values. Freshwater mussels are considered potent ecosystem engineers, their presence altering energy exchange between water column and sediments, and enhancing benthic productivity. Mussel populations are threatened by climate change and anthropogenic alteration of aquatic ecosystems, and worldwide have undergone drastic population declines with at least 22 species extinctions recorded. This systematic quantitative literature review examined the global literature relating to freshwater mussel ecology, using a text mining and topic modelling approach to identify key themes of research and knowledge gaps, including areas of taxonomic and geographical underrepresentation to guide future research. Taxa associated with North America and Europe (Unionidae and Margaritiferidae) are the focus of the vast majority of ecological literature, while other taxa and regions are less well studied, particularly in terms of the role of mussels in shaping ecosystems. Despite limited research, existing evidence indicates that Hyriidae, which occur in Australia, New Zealand and South America, also fulfill ecosystem engineer functions. The increasing pressure on freshwater supplies with growing human population and climate change indicates that we desperately need a better understanding of the role of mussels in water quality and aquatic ecosystem functioning, particularly in Australia.