This mixed methods study with an Explanatory Design is an exploration of students' language learning motivation as it relates to their attrition from a language immersion program. A total of 131 students who had graduated from five public elementary immersion schools responded to surveys, and 33 of those students were interviewed. Data analysis procedures included a theme analysis of the interview data, a statistical analysis of the survey data, and an integrated consideration of the qualitative and quantitative findings. It was found that mixed methods research can be uniquely revealing about social psychological constructs such as motivation, it can offer new perspectives where previous studies were contradictory, and it can accommodate multiple theoretical frameworks. (Contains 2 notes, 3 tables, and 1 figure.)