Biohydrogen production is a promising avenue for sustainable energy generation, and nanocomposites/nanomaterials offer exciting opportunities to enhance its efficiency and viability. This chapter explores the diverse applications of nanomaterials in different stages of biohydrogen production, including dark fermentation, photo-fermentation, biophotolysis, microbial electrolysis cells (MECs), photocatalytic hydrogen generation, and membrane-based technologies. Nanomaterials play crucial roles in enhancing efficiency, environmental sustainability, and economic viability throughout these processes. Moreover, this work addresses investigations into the toxicity of nanoparticles in biohydrogen production, as well as future outlooks. Overall, this study emphasizes the significant contributions of nanomaterials towards advancing biohydrogen production as a crucial renewable energy source for a sustainable future.