This report describes the development, standardization, and validation of two parallel forms of the Officer Selection Battery, a 2-hour, group administrable, paper and pencil test for assessing men and women applying for the Reserve Officers Training Corps (ROTC). Based on an extensive job analysis, 1,400 experimental items in 12 job areas were developed and administered to 3,306 college juniors who were enrolled in the Advanced ROTC program. This group was stratified to conform to the 1980 national distribution of Scholastic Aptitude Test scores, and weighted to reflect appropriate ethnic and gender representation. Item analyses were performed using faculty evaluations of each tested cadet's officer potential as criteria. Items that would yield the most valid tests with the least gender or ethnic impact were selected for the final forms. For standardization, the tests were administered to college sophomores in military science courses. Criterion-related validity was investigated twice using samples of senior ROTC cadets and Second Lieutenants in their first assignments. On the basis of the correlation and regression analyses performed, the Officer Selection Battery was concluded to be empirically and content valid and of comparable validity for ethnic and gender subgroups, with no indication of differential validity or regressions. Appendices include definitions of identified dimensions of officer job performances, test item types, the plan for addressing equal employment fairness in the Officers Selection Battery, weighting procedures, readability measures, and a comparison of the Officer Selection Battery with two tests in use as selectors for army officer precommissioning training programs. (JAZ)