Explanations of sex-related differences in spatial ability emphasizing the role of sex-differentiated experience have not been supported by direct measurement of spatial activities during adolescence, the period when these differences seem to increase. The present research involved development of a scale to measure the spatial experience of adolescents and adults. In Study 1, a list, as complete as possible of adolescent activities was compiled and given to undergraduate judges for ratings of involvement of spatial skills and sex-typing. Judges also indicated whether they had participated in each activity. Activities considered spatial by 75% or more of the judges were used to develop a spatial experience questionnaire. Judgments of the spatial nature of tasks were positively correlated with judged masculinity and with greater male than female participation. In Study 2, participation in spatial activities by undergraduates was correlated with spatial ability as measured by the Differential Aptitude Test. The activity questionnaire should prove useful in studying the development of spatial ability in adolescents and adults.