A STUDY WAS MADE TO DETERMINE THE EFFECT OF HETEROGENEOUS AND HOMOGENEOUS GROUPING IN NINTH-GRADE ENGLISH CLASSES. ON THE BASES OF IQ AND READING LANGUAGE SKILLS, STUDENTS WERE GROUPED AT THREE ABILITY LEVELS AND PLACE IN HETEROGENEOUS, HOMOGENEOUS SUPERIOR, HOMOGENEOUS SLOW, AND HOMOGENEOUS AVERAGE CLASSES. TEACHER VARIABLES WERE REDUCED BY HAVING THE SAME TEACHER ASSIGNED TO A HETEROGENEOUS CLASS AND A HOMOGENEOUS CLASS. RESULTS WERE DISCUSSED IN REFERENCE TO ASSESSMENT MEASURES, CLASS DISCUSSION, TEACHER RATINGS, PEER RATINGS, SELF-CONCEPT, AND ATTITUDE TOWARD THE EXPERIMENTAL ENGLISH CLASS AND SCHOOL. PLACEMENT IN HOMOGENEOUS CLASSES DID NOT SIGNIFICANTLY CHANGE THE RELATIVE ACHIEVEMENT STATUS OF ANY GROUP AS MEASURED BY STANDARDIZED TESTS. IN CLASS DISCUSSIONS, THE LEVEL OF VOCABULARY AND PATTERNS OF PARTICIPATION DIFFERED WITH ABILITY LEVEL AND TYPE OF GROUPING. SUPERIOR STUDENTS PARTICIPATED THE MOST IN HETEROGENEOUS CLASSES. THE LEVEL OF WORDS IN HETEROGENEOUS CLASSES WAS HIGH, SHOWING THE DOMINANCE OF SUPERIOR STUDENTS. SLOW STUDENTS PARTICIPATED MORE IN HOMOGENEOUS CLASSES. TEACHER RATINGS INCLUDED GENERAL EVALUATION OF PERFORMANCE, SIX INTELLECTUAL RATINGS AND ONE SOCIAL RATING, AND COURSE GRADE. ALL RATINGS SHOWED THAT IN HETEROGENEOUS CLASSES, SUPERIOR AND AVERAGE STUDENTS WERE VIEWED AS VERY DIFFERENT FROM SLOW STUDENTS, IN HOMOGENEOUS CLASSES, WHILE SUPERIOR STUDENTS WERE STILL RATED HIGHEST, THE DISTINCTION BETWEEN AVERAGE AND SLOW STUDENTS DISAPPEARED. IN HETEROGENEOUS CLASSES, SUPERIOR STUDENTS WERE CHOSEN MOST OFTEN IN PEER RATINGS ON INTELLECTUAL AND SOCIAL ITEMS, IN HOMOGENEOUS CLASSES AT LEAST SOME SLOW OR AVERAGE STUDENTS WERE NONIMATED. IN HETEROGENEOUS CLASSES SELF-CONCEPTS CONFORMED CLOSELY TO TRUE ABILITY LEVELS, IN HOMOGENEOUS CLASSES, ALL GROUPS SAW THEMSELVES AS CLOSE TO AVERAGE.