In this study we analyse the relationship between Mexican students' enrolment in the International Baccalaureate (IB) Diploma Programme (DP) and their college preparedness using a case-study methodology. We found that from the Mexican schools that offer the IB DP, most IB students are fairly successful in their college applications, such that the majority enrols at among the most well-regarded post-secondary institutions in Mexico. The possibility that IB DP grades and/or examination records might help boost students' college admissions options does not seem to be a primary motivating factor for students' IB DP enrolment. Rather, we found that students enrol in the IB DP because they think it will help prepare them to successfully handle college-level work. Students and educators believe that various aspects of the IB DP prepare them for college-level work, including the Theory of Knowledge course, the Extended Essay and the Creativity, Action and Service programme.