The universal basic income has become a widely discussed measure in policy circles around the world. In this review, we cover the evidence relevant to its potential impact in the US, and in developed countries more generally. Many studies find no statistically significant effect of an unconditional cash transfer on the probability of working. In the studies that do find an effect on labor supply, the effect is small: a 10% income increase induced by an unconditional cash transfer decreases labor supply by about 1%. The evidence shows that an unconditional cash transfer can improve health and educational outcomes, and decrease criminality and drug & alcohol use, especially among the most disadvantaged youths.