A SOCIAL COMPETENCY SCALE DESIGNED TO RATE PRESCHOOL CHILDREN AGED TWO YEARS, SIX MONTHS THROUGH FIVE YEARS, SIX MONTHS WITHIN A NURSERY SCHOOL CONTEXT WAS DEVELOPED AND STANDARDIZED. AFTER EXTENSIVE OBSERVATIONS OF PRESCHOOLERS, DISCUSSIONS WITH PRESCHOOL PERSONNEL, AND REVIEWS OF AVAILABLE MATERIAL THE FIRST FORM OF THE SCALE WAS WRITTEN, BASED ON CERTAIN PREDETERMINED CRITERIA. THE SCALE ITEMS WERE INITIALLY JUDGED BY GROUPS OF PRESCHOOL TEACHERS AND TEACHER EDUCATORS WHO RANKED ITEMS IN TERMS OF THEIR IMPORTANCE IN REGARD TO CHILDREN'S SOCIAL COMPETENCE. AN INITIAL SAMPLE OF 1165 CALIFORNIA CHILDREN WERE RATED, AND 30 ITEMS WERE SELECTED FOR THE FINAL SCALE FORM. A REPRESENTATIVE SAMPLE OF CHILDREN IN NURSERY SCHOOLS THROUGHOUT THE UNITED STATES PROVIDED THE NORMING POPULATION. TEACHER RATINGS WERE OBTAINED FOR 800 CHILDREN, EQUALLY DISTRIBUTED BY AGE (2, 3, 4, AND 5), SEX, AND OCCUPATIONAL LEVEL (LOW AND HIGH). STATISTICAL TREATMENT OF THE DATA BY A THREE-WAY ANALYSIS OF VARIANCE INDICATED THAT THE SCALE RELIABLY DISCRIMINATED BETWEEN VARIOUS AGE GROUPS. F RATIOS FOR THE MAIN EFFECTS WERE SIGNIFICANT BEYOND THE .01 LEVEL. NONE OF THE INTERACTIONS WAS SIGNIFICANT. SEPARATE NORMS WERE MADE FOR EACH OF THE FOUR AGE GROUPS BY SEX AND OCCUPATIONAL LEVEL. APPENDICES INCLUDE THE RATING SCALE WITH ITEM RATING PERCENTILES AND NORMING PERCENTILES. (MS)