Through an examination of measurement invariance, this study investigated whether attachment-related dimensions (i.e., secure base, safe haven, and negative interactions as measured with the Network of Relationships Inventory—Behavioral Systems Version) have the same psychological meaning for early adolescents in their relationships with parents and teachers. Data were gathered for a sample of 297 families with an adolescent in Grade 7 (M _age = 11.40; 62% boys). The results indicated that perceived attachment-related dimensions have a similar meaning in parent–child and teacher–child relationships (weak metric invariance), but that no direct comparison of observed means should be made (lack of strong metric invariance). In addition, it seemed that teachers fulfill the function of secure base rather than safe haven in early adolescence.