Examined significance of close, cross-sex friendships to socioemotional functioning of tenth through twelfth graders. Found that having close, cross-sex friend was common and increased with age. Adolescents reported more companionship in same- versus cross-sex friendships. There were sex and age differences in support from cross- versus same-sex friendships. Having close, cross-sex friends was associated with lower perceived social acceptance. (Author/KB)