Using data from the American Time Use Survey, I find that a first-born child receives 20-30 more minutes of quality time each day with his or her parent than a second-born child of the same age from a similar family. The birth-order difference results from parents giving roughly equal time to each child at any point in time while the amount of parent-child quality time decreases as children get older. These results provide a plausible explanation for recent research showing a very significant effect of birth order on child outcomes. (Contains 14 tables, 2 figures, and 12 footnotes.)