This study examined the relationships between spatial ability, mathematics achievement, and sex for students in grades 2-7. Four spatial tests (embedded figures, serial integration, coordination of viewpoints, and rotation and development of surfaces) were used to measure spatial ability; sex and mathematics achievement, as measured by the Iowa Test of Basic Skills, were determined from school records. Data for the 90 subjects were submitted to four three factor (grade x sex x mathematics achievement) analyses of variance. All analyses yielded results indicating a relationship between spatial and mathematical ability. For two of the tests, sex differences favoring males were revealed. (SD)