Bubbles are always encountered for gas-liquid two-phase flow in microchannels, and have potential applications in chemical engineering, polymer engineering, food engineering, and biological engineering. The bubble formation and breakup dynamics in microfluidic devices are reviewed in this article. The effects of the confinement of microchannels and the fluid flow on bubble formation and breakup dynamics are highlighted. The dynamical evolution of the gas-liquid interface during bubble formation and breakup in confined spaces is analyzed. The manipulation for the bubble formation and breakup in microfluidic devices is presented. The scaling laws for the bubble size in such devices are also reviewed. Finally, the key issues for the scaling-up of bubble generation in microfluidic devices are demonstrated. (C) 2015 Elsevier Ltd. All rights reserved.