The present study is a multi-phased, mixed methodological investigation of teacher interest. In Phase 1, 12th grade students nominated and quantitatively evaluated teachers who were perceived as helping them learn and become interested in a high school core subject. Exploratory factor analysis revealed that student perceptions of teacher interest were represented by items related to both teacher effectiveness and individual differences. In Phase 2, the top three nominees and a stratified random sample of their current students were examined using qualitative research methods. Findings indicate that teacher interest is a complex construct comprised of cognitive, affective, motivational, and volitional dimensions.