The current energy supply depends on fossil fuels which have increased carbon dioxide emissions leading to global warming and depleted non-renewable fossil fuels resources. Hydrogen (H2) fuel could be an eco-friendly alternative since H2 consumption only produces water. However, the overall impacts of the H2 economy depend on feedstock types, production technologies, and process routes. The existing process technologies for H2 production used fossil fuels encounter the escalation of fossil fuel prices and long-term sustainability challenges. Therefore, biohydrogen production from renewable resources like biomass wastes and wastewaters has become the focal development of a sustainable global energy supply. Different from other biohydrogen production studies, this paper emphasizes biohydrogen fermentation processes using different renewable sources and microorganisms. Moreover, it gives an overview of the latest advancing research in different biohydrogen process designs, modeling, and optimization. It also presents the biohydrogen production routes and kinetic modeling for biohydrogenation. •Review on biohydrogen process design, modelling, and optimization.•Comparison of biohydrogen process designs including continuous, batch, or semi-batch processes.•Kinetic equations with optimized parameters are hard to be converted into universal predictive models.•Identification of some possible future research directions.