Recent research has shown the increasing number of non-native English-speaking teachers (NNEST) around the world. Research has also considered different attributes these teachers need to have in order to be effective in their professional practices. In this light, this study examines the relationship between NNEST's language proficiency and their sense of self-efficacy in relation to students' perceptions about teacher efficacy in three different dimensions: Efficacy for instructional strategies, efficacy for classroom management, and efficacy for student engagement. A correlational quantitative design was used in which six private high schools from Cuenca, Ecuador, participated. Seventeen teachers from these schools were requested to provide an English proficiency certificate and respond to a self-efficacy survey. In the meantime, their 661 students completed a teacher's efficacy survey. The results revealed that although there are teachers who have a good level of language proficiency, according to their students, it is not necessarily an indicator of efficacy in their practices. Suggestions for further research that might help to explain the current situation are given.