Higher birth order positions are often associated with poorer outcomes, possibly due to fewer resources received within the household. Using a sample of PSID-CDS children, we investigate whether the birth order effects in their outcomes are due to unequal allocation of the particular resource represented by maternal quality time. OLS regressions show that the negative birth order effects on various test scores are only slightly diminished when maternal time is included among the regressors. This result is confirmed when we account for unobserved heterogeneity at the household level, exploiting the presence of siblings in the data. Our evidence therefore suggests that birth order effects are not due to differences in maternal quality time received.