Elementary school children, 20 boys and 20 girls, served as subjects in this investigation designed to determine how children sex-typed each of three different motor activities and to study their success predictions before and after cross-sex competition. Results of the study indicated that both boys and girls sex-typed a motor task requiring strength, speed, and power as a “male” activity, while the two other motor tasks were characterized as “male-female.” The self-confidence levels of girls, as measured by success predictions were lower than boys prior to competition but only for the “male” activity. After cross-sex competition in which girls succeeded as often as the boys, self-confidence of girls was no different than for boys. There were no sex differences in postcompetition state anxiety levels. All subjects regardless of sex were more threatened after competing in a “male” as opposed to a “male-female” activity, and they experienced lower state anxiety following successful rather than unsuccessful competition.