Analyzing the savings behavior of a large sample of identical and fraternal twins, we find that genetic differences explain about 33 percent of the variation in savings propensities across individuals. Individuals are born with a persistent genetic predisposition to a specific savings behavior. Parenting contributes to the variation in savings rates among younger individuals, but its effect decays over time. The environment when growing up (e.g., parents’ wealth) moderates genetic effects. Finally, savings behavior is genetically correlated with income growth, smoking, and obesity, suggesting that the genetic component of savings behavior reflects genetic variation in time preferences or self-control.