Teachers’ self-efficacy and value represent two central components of their motivation. However, there is a scarcity of knowledge regarding the relevance of value for teaching quality and student outcomes, as well as the extent to which interrelations depend on contextual resources and demands. Engaging students in their learning is an essential aspect of teachers’ work which should promote warm and positive relationships between them and their students. Not only teachers’ self-efficacy for student engagement, but also the value they attach to being able to engage students, should be important for teacher-student relationship quality. Using longitudinal structural equation models, we analyzed relations between self-efficacy and value for student engagement, reported teacher-student relationships, and the potential moderating roles of perceived excessive work demands and the resource of school belonging. Data from 395 Australian teachers in primary and secondary schools encompassed 3 timepoints from the end of teacher education, during teachers’ early career (average 3 years teaching), and midcareer (average 10 years teaching). Informed by social cognitive, expectancy-value and job demands-resources theories, key findings revealed that teachers’ reported relationships with their students at midcareer were predicted only at low levels of perceived excessive demands, by early career self-efficacy and early career value in interaction with self-efficacy. At midcareer, value associated with teacher-reported relationships with students only at low levels of excessive demands, and school belonging. Conversely, perceived teacher-student relationship in early career predicted teachers’ value for student engagement at midcareer. Implications for theory, teacher education and teachers’ professional practice are discussed.