Glycerol, a commodity by-product of the biodiesel industry, has value as a fuel feedstock and chemical intermediate. It is also a simple prototype of sugars and carbohydrates. Through catalytic partial oxidation (CPOx), glycerol can be converted into syngas without the addition of process heat. We explored the CPOx of glycerol using a nebulizer to mix droplets with air at room temperature for reactive flash volatilization. Introducing this mixture over a noble-metal catalyst oxidizes the glycerol at temperatures over 600 °C in 30–90 ms. Rhodium catalysts produce equilibrium selectivity to syngas, while platinum catalysts produce mainly autothermal non-equilibrium products. The addition of water to the glycerol increases the selectivity to H2 by the water gas shift reaction and reduces non-equilibrium products. However, water also quenches the reaction, resulting in a maximum in H2 production at a steam/carbon ratio of 2:3 over a Rh-Ce catalyst. Glycerol without water produces a variety of chemicals over Pt, including methylglyoxal, hydroxyacetone, acetone, acrolein, acetaldehyde, and olefins.