A test measuring testwiseness was administered to 811 pupils in grades 3, 5, and 7 in the Tucson Unified School District. The pupils represented four ethnic groups: American Indian, Anglo, Black, and Hispanic. By controlling for reading ability using scores on a standardized reading test, the California Achievement Tests (CAT) or Comprehensive Tests of Basic Skills (CTBS), as a covariate, significant sex-by-ethnicity interactions were found. The use of reading comprehension as a covariate resulted in findings substantially different from previous research or from what may be concluded from looking at obtained testwiseness scores as a dependent variable. Due to small numbers of pupils in some groups and inconsistencies across grades, specific group results were regarded as extremely tentative. (Author/RL)