Crick and Dodge's (Psychological Bulletin 115:74-101, 1994) social information processing model has proven very useful in guiding research focused on aggressive and peer-rejected children's social-cognitive functioning. Its application to early childhood, however, has been much more limited. The present study responds to this gap by developing and validating a video-based assessment tool appropriate for early childhood, the Schultz Test of Emotion Processing-Preliminary Version (STEP-P). One hundred twenty-five Head Start preschool children participated in the study. More socially competent children more frequently attributed sadness to the victims of provocation and labeled aggressive behaviors as both morally unacceptable and less likely to lead to positive outcomes. More socially competent girls labeled others' emotions more accurately. More disruptive children more frequently produced physically aggressive solutions to social provocations, and more disruptive boys less frequently interpreted social provocations as accidental. The STEP-P holds promise as an assessment tool that assesses knowledge structures related to the SIP model in early childhood.