The present disclosure relates to a microfluidic vaporizer, an aerosol delivery device that may include such vaporizer, and methods for forming an aerosol. A microfluidic vaporizer can comprise a substrate that defines: a reservoir configured to hold a liquid; a heater adapted to vaporize the liquid; and a capillary channel configured for movement of the liquid from the reservoir to the heater. An aerosol delivery device can comprise a shell and a microfluidic vaporizer. The microfluidic vaporizer and aerosol delivery device can be used for forming aerosols with precise and reproducible compositions.