CO2 absorption is a key to alleviating the environmental consequences of fossil fuel combustion, which is a major source of global CO2 emission. Membrane contactors have showcased several competitive advantages in CO2 absorption over conventional gas-liquid contactors (e.g., packed towers), such as a large mass-transfer area and a safe operation owing to the membranes that physically separate the gas and liquid phases. This Review discusses the state-of-the-art studies related to CO2 absorption using membrane contactors, with focuses on membrane materials, liquid absorbents, process design, and pilot-scale demonstration of membrane contactor processes. Critical challenges in membrane contactor-based CO2 absorption processes, such as membrane fouling and pore wetting, are also discussed.