Hydrogen is a clean, renewable, and versatile energy carrier that could potentially replace fossil fuels. However, existing hydrogen production technologies require high energy inputs from combustion of fossil fuels, which is unsustainable in long-term. On the contrary, photobiological hydrogen production from microorganisms is an attractive alternative technology, in which the energy is derived from natural resources, such as sunlight and water, which are abundantly available. Research on microalgae-based hydrogen production has recently reached a significant milestone, but has yet to become a mature technology within a reasonable time. This chapter discussed recent developments and limitations of biohydrogen production from microalgae. Strategies to improve microalgae biohydrogen production and factors to be considered to scale-up the process are also outlined in this chapter. © 2019 Elsevier B.V. All rights reserved.