This chapter examines mastery motivation in ethnic minority groups and to place this work in the context of cross-cultural endeavours in psychology. It describes the consistent with the notion of effectance motivation proposed by and the operationalization of mastery motivation by Yarrow and his colleagues. The chapter explores mastery motivation in sub-cultural and cross-cultural samples of Hispanic Americans and Puerto Ricans. It outlines the necessary adaptations to the standardized mastery motivation tasks, and presents reliability and validity evidence for the adapted tasks. The chapter concerns the psychological processes underlying mastery motivation which might be explored in future sub-cultural or cross-cultural work. It analysis the scores from the standardized mastery motivation tasks involved comparing the pleasure and persistence scores of the Hispanic sample to the currently available norms. Because the range of scores for mastery pleasure is usually very small, the norms for pleasure are presented as a dichotomous variable indexing any pleasure versus no pleasure.