In recent years instructor credibility has been considered one of the most significant variables in the teacher-student communication, constituting a fundamental element in the teaching-learning process. Research on instructor credibility has mainly focused on analyzing the variables that affect instructor credibility and their impact on the teaching-learning process. Thus, the purpose of this study was to establish the state of the art of teacher credibility through a review of the existing literature, establishing the variables that affect it and determining its impact on the teaching-learning process. A bibliographic search was carried out in Web of Science, Scopus, PsycINFO and ERIC databases, selecting for the review a total of 64 scientific articles, published between 1980 and 2018, that fulfilled the established inclusion criteria. After the analysis of the studies included in the review, in relation to the variables that affect teacher credibility, 8 categories were identified while, with regard to the impact of teacher credibility on the teaching-learning processes, 5 categories were identified, including in each of them the main contributions of the studies included in the analysis. Based on the obtained results, the influence of teachers' behaviors on students' evaluations and on the teaching-learning process is highlighted, which indicates the need for teachers to have positive behaviors to be perceived by students as credible people and, therefore, to positively affect the teaching-learning process.