Student teachers taught a program to reduce stereotyped beliefs among children from first to sixth grade. The program was developed on the basis of constructivist theory and involved teaching strategies designed to lead children to question existing beliefs. Compared to children in a control group, the children in the two experimental conditions were shown to have significantly less stereotyped beliefs on completion of the program. The effects of the intervention were relatively greater among boys and younger children. The effects of the program were noticeable 1 year afterwards in a subsample of girls who participated in the study. It is suggested that this approach had considerable potential for classroom application. Relevance: This study shows how constructivist theory may be applied in classrooms so that children can be facilitated in their re-thinking about gender stereotypes.