Background: Social isolation measures by the COVID-19 pandemic have impacted teaching work. In an "Emergency Remote Teaching" (ERT) context, it is relevant to investigate the factors that affect teachers' self-efficacy. Methods: A total of 289 teachers from schools in southern Spain have participated in this study. They have been asked about their levels of burnout, engagement, and resilience. Comparisons were made by groups in accordance with sex, type of center they belonged to, school social context, and educational level in which the teacher taught. Using a Structural Equations Model, the multivariate relationships between the variables related to burnout, engagement, and resilience were described. Results: During the ERT, teachers' self-efficacy was influenced by the 3 factors: burnout--exhaustion and cynicism--engagement, and resilience. During the ERT, the teachers in semi-private and private centers showed greater self-efficacy. In turn, the teachers in childhood and primary education showed a significantly higher level of work engagement than the teachers in compulsory and post-compulsory secondary education. Conclusions: The results in relation to ERT are discussed in the context of the exceptionality and universal globality of the pandemic phenomenon and the complex self-perception of the social value of the teaching function.