In this article, the authors report on the development of an interest inventory (the Maree Career Matrix) for South Africans with a minimum of Grade 9 second language English or Afrikaans proficiency. The instrument was completed by 1106 learners in Grade 11 in the Gauteng, Mpumalanga, and North West provinces of South Africa. Rasch analysis was done; inter-category correlations, reliability coefficients, and differential item functioning values were calculated; and validity and norm tables were established. We concluded that the Maree Career Matrix is easy to use and has good psychometric qualities, takes relatively little time to administer, provides reliable and valid results, is standardised, and can be applied to large groups with relative ease. Additional research is needed to gather data on the profiles of people in other age brackets and to trace their progress, the aim being to further investigate and enhance the predictive value of the Maree Career Matrix.