A multiple study mixed methods research design was used to examine how gifted English as a Foreign Language (EFL) high school students in Vietnam form their career intentions. In the first study, interview data collected from 25 participants were analyzed using grounded theory to develop models that describe the formation of career intentions. In the second study, survey data collected from 512 participants were analyzed using structural equation modeling procedures to quantitatively test and refine the qualitative models developed in the first study. In the final third study, structural equation modeling was again used on data collected from 602 participants using a refined survey to quantitatively retest and refine the models developed in both of the earlier two studies. The finally accepted optimal model highlighted the importance of career interest, career self-efficacy, and career prospects in the formation of the career intentions of gifted EFL high school students in Vietnam.