Many researchers have called for a broadening of the theoretical base of language teacher development programs to include gathering information not only on what teachers do in the classroom, but also on what they know, and how this knowledge is transferred to their teaching behavior, especially as they gain more experience in the classroom. However, in the field of teaching English to speakers of other languages (TESOL), studies of teachers' knowledge base and its development are relatively scarce (Borg, 2003; Gatbonton, 2000; Johnston & Goettsch, 2000). This qualitative study is a partial replication of Gatbonton's (2000) study, using her stimulated recall methodology and coding features, but it also extends her study by incorporating a number of key changes. The data derive from intact classes of low intermediate to advanced level students in general English, Business English, and Cambridge Advanced Certificate classes. The study examines the reports of 4 teachers, with differing amounts of TESOL teaching experience, on their thinking about their activities in these classrooms.