This special issue aims to prompt reflection on the mutual contribution of attachment theory, on the one hand, and teacher–child relationship research, on the other, by bringing together conceptual and empirical contributions taking an attachment perspective on teacher–child relationships. In this introductory article, we contend that the teacher can be regarded as an ad hoc attachment figure with a safe haven and secure base function, although for most children the relationship with the teacher is probably not an attachment bond. Furthermore, we explain how attachment theory and research: (1) shape the way in which “high quality” teacher–child relationships are conceptualized and operationalized; (2) highlight the importance of teacher sensitivity to children's needs, as a central proximal determinant of relationship quality; (3) guide research hypotheses regarding the consequences of teacher–child relationship quality and the intervening mechanisms; and (4) inspire the development of interventions to improve teacher–child relationships.

In recent developmental theorizing, it has been hypothesized that teacher–child conflict and children's externalizing behavior affect one another reciprocally over time. However, the relation between teacher–child conflict and externalizing behavior has been mainly studied from a unidirectional point of view. Therefore, this study aimed to test the hypothesis of bidirectionality by means of a cross-lagged longitudinal design with kindergarten teacher reports on core variables at 3 measurement occasions in 1 year. Structural equation modeling with data of 148 kindergartners provided evidence for the hypothesis of bidirectionality. Specifically, results supported a transactional sequence in which children's aggressive behavior at the beginning of kindergarten led to increases in teacher–child conflict midyear, which in turn led to an increase of aggressive behavior at the end of the kindergarten school year.