The purposes of the research are to: (1) find out how is teacher‘s efficacy in teaching vocabulary reflected in their classroom practices; (2) find out what factors influence the teacher‘s efficacy in vocabulary teaching and how those factors influence the teacher‘s efficacy in vocabulary teaching. This qualitative study was conducted in four different universities. There was one teacher from each university who participated on this study as participant. Each teacher was interviewed and observed in 2 SKS teaching period. In addition, the data consisted of qualitative data. The qualitative data were collected through interview, observation, and documents analysis, and were analyzed using Interactive Model. The result reveals that: (1) the teachers who participated on this study fulfilled the teacher‘s efficacy indicators, as follows; (1a) realizing the importance and the goal of vocabulary teaching, the teachers use diverse teaching strategies to achieve the goal; (1b) the teachers also managed and organized the class to achieve students‘ mastery in vocabulary; (1c) the teachers planned what would be taught in their vocabulary class by preparing the materials; (1d) the teachers were enthusiastic in teaching vocabulary. Those teachers‘ efficacy was reflected in their teaching practices in vocabulary teaching. On their teaching practices, the teachers used lecturing, cooperative learning, and group discussion to enable their students master vocabulary and use the vocabulary in various contexts. Besides using additional reference in preparing the materials, the teachers who were enthusiastic in teaching vocabulary above, also tend to create such a conducive and comfortable class to enable the students master the materials. Then, there are some factors which influence teacher‘s efficacy in teaching vocabulary. The factors are: (1) references; (2) feeling of having competence; (3) facilities; (4) students‘ enthusiasm; (5) experience. From the findings of the study, it can be theorized that teachers‘ practices in vocabulary teaching is greatly influenced by their efficacies. Therefore, the teachers should first enrich their efficacies. Teacher‘s Efficacy can lead to such an effective vocabulary teaching.
Keywords: teacher’s efficacy, vocabulary teaching, qualitative study