A discussion of the relationship between teacher, learner, and instructional materials in second language teaching using the communicative approach argues that the teacher is the primary element in instructional effectiveness, without which the other salient features of the approach, learner-centeredness and appropriate materials, can not be implemented. It is proposed that teachers can be enthusiastic about their classrooms and about new approaches if they have been encouraged in their training experiences and attained a degree of proficiency in the language they teach. In addition, socioeconomic security and stability are seen as essential to teacher effectiveness beyond a minimal standard. (MSE)