This study assessed level and structure differences across sex and ethnic groups on a newly developed multiple aptitude battery, called the Ball Aptitude Battery (BAB), and established and examined the concurrent and differential validities of the battery relative to different groups. The 17 Ball ability variables are: clerical test; idea fluency; tonal memory; pitch discrimination; rhythm memory; inductive reasoning; word association; writing speed; paper folding; vocabulary; ideaphoria; finger dexterity-left; finger dexterity-right; grip-left; grip-right; shape assembly; and analytical reasoning. BAB test data were collected from 1,009 high school students from Illinois and Texas representing both sexes and three ethnic group (Black, White, Hispanic). Additional criterion data (overall grade point average and 10 academic course grades) were obtained for 801 students. Data showed that ethnic group and sex variables were associated with level differences, but not with the pattern and structure of abilities as measured by the Ball Aptitude Battery. Also, the simplicity of factor patterns indicate that redundancy is minimal for the tests. Findings of few significant differential validities for sex and ethnic groups indicate that the same battery of ability tests can serve for different ethnic and sex groups. (Author/BS)