Little research has examined whether social information processing (SIP) measures from early childhood predict externalizing problems beyond the shared association with familial risk markers. In the present study, family antecedents and first-grade externalizing behaviors were studied in relation to preschool and 1st-grade SIP using data from the U.S. National Institute for Child Health and Human Development Study of Early Child Care (N=1,364). A subgroup of low-risk children reported only benign attributions in preschool and had few externalizing problems in 1st grade according to both teacher and mother reports. After controlling for gender and cognitive functioning, the authors found that maternal education and authoritarian attitudes were key predictors of this "Pollyanna preschooler" status and of SIP in 1st grade. However, small effect sizes for SIP variables underscore the need for new approaches to measurement and for further research on moderators of the link between SIP and children's behavior.