The Young Children's Self-Concept Scale, a 40-item revision of the Piers-Harris Children's Self Concept Scale, was designed specifically for young children. Its validity was investigated by comparing self concept scores to teachers' ratings of self concept. The sample included twenty teachers and 459 students in grades 1-4. Factor analyses were conducted according to age (grades 1-2 and grades 3-4) and sex of student. Correlation coefficients between teacher rankings and self concept scores ranged from -.01 to .58, with a median correlation of .32. Factor analyses examining maturational differences generated 13 factors for grades 1-2 and 14 factors for grades 3-4. Three factors were important in both age groups: (1) body image; (2) student behavior, particularly troublesome behavior; and (3) feelings of adequacy and happiness. These factors also accounted for 55% of the total variance for each sex. Further examination indicated sex differences in responses to seven of the 40 test items. It was concluded that the Young Children's Self-Concept Scale provided reliable measurements at the primary level, and that self concept factor structure was remarkably consistent between sexes and grade levels. (GDC)