Using longitudinal data from a sample of 456 focal children in the National Survey of Families and Households (NSFH), this study examined two research questions: (a) Does corporal punishment of young children (ages 2–4 at baseline) predict increases in levels of externalizing and internalizing problems over a 5-year study period? (b) Does the religion of the mother—specifically, her conservative Protestant affiliation and conservative beliefs about the Bible—moderate the estimated net effects of corporal punishment? Results revealed that early spanking alone was not associated with adjustment difficulties, but spanking that persisted into or began in middle childhood was associated with difficulties. In contrast to their counterparts from other (or no) religious backgrounds, children whose mothers belonged to conservative Protestant groups exhibited minimal adverse effects of corporal punishment. Several conclusions, limitations, and promising directions for future research are identified.