The gap between girls' and boys' performance on object control skills in early childhood is pervasive. The purpose of this study was to examine outcomes of a modified motor skill intervention for preschoolers, Successful Kinesthetic Instruction for Preschoolers, Gender-Equity. Participants (3-5 years of age) from an urban Head Start center were assigned to an intervention (n = 86) or control condition (n = 58). The sample was approximately divided by sex (control: 50% girls, 50% boys, Successful Kinesthetic Instruction for Preschoolers, Gender-Equity: 43% girls, 57% boys) and ethnically representative of the school population (Black = 67%, Latinx = 23%, White = 6%, and Other = 4%). Generally, findings suggest that the intervention was effective, especially in reducing male participants' in-group bias, with fewer male participants indicating that only boys can engage in object control skills after the intervention. These findings have implications for the design of interventions and physical education classes that communicate equitable messages about girls' and boys' opportunities to engage in object control skills.