Test results are presented from the 11th year of the Arizona Pupil Achievement Testing Program, administered as mandated by the state legislature, which requires that a nationally standardized norm-referenced achievement test in reading, grammar, and mathematics be given to students in grades 2 through 11, with representative samples tested in grades 1 and 12. In 1991, the Riverside Basic Skills Assessment Program was used, consisting of the Iowa Tests of Basic Skills for grades 1 through 8 and Tests of Achievement and Proficiency for grades 8 through 12. A total of 442,620 students in grades 2 through 11 and 31,145 students in grades 1 and 12 were tested on April 1st through 12th of 1991. Students collectively scored in the average range in reading, language, and mathematics; and were performing at about the same level of achievement as students across the nation based on 1987-88 national norms. Gender differences are identified, and the performance of racial and ethnic groups is discussed. Twenty-six figures and 38 tables illustrate the results for the individual grades. The separately bound appendix contains the 1991 percentile ranks for reading, language, and mathematics by school district in 141 pages of tables in appendixes A, B, and C. (SLD)