Changing demographic patterns present teachers with students of diverse ethnic backgrounds, learning abilities, family structures, and linguistic traditions. This study assessed the impact of classroom diversity on Israeli teachers' perspectives of the their workplace. Generally favorable perceptions of multiculturalism in the abstract conflict with the reality of greater job difficulty. This disparity may produce job dissatisfaction. This problem is compounded by the fact that less experienced professionals are more frequently assigned to diverse classrooms. Three-hundred seventy teachers, mostly female, responded to a questionnaire distributed to 883 secondary schools in one medium-sized Israeli city. Teachers from diverse classrooms were likelier to report lower levels of student academic achievement, lack of parental support, larger class sizes, and many disciplinary problems. Females with relatively shorter careers are assigned to more diverse classrooms. The effects on teachers' perceptions of their workplace are strong, indicating greater job dissatisfaction and less cooperation with school leaders. Despite the fact that classroom diversity plays a vital role in teachers' professional lives, it receives less attention as an important variable in other studies than it deserves. (Contains 21 references.) (TEJ)