Secure base scripts (SBS) are thought of as the earliest, rudimentary mental representations of attachment, comprising temporally and causally related events occurring in interactions between children and their attachment figures. SBS have been studied in preschool children, adolescents and adults, but there is little research relating SBS to other attachment measures in middle childhood. Here, the Secure Base Script Test (SBST), a narrative-based measure of attachment scripts in middle childhood, was developed and evaluated. In two studies with 7-12-year-olds (total N = 261), high internal consistency, inter-rater reliability and discriminant validity was established. SBS knowledge was consistent across different contexts and relationships and converged strongly with security and coherence in representations assessed by the Friends and Family Interview and moderately with self-reported attachment security. Furthermore, SBS knowledge predicted children's capacity to respond to distress in an adaptive way. Our findings may be taken to provide some first evidence for generalized scripted attachment knowledge already in middle childhood.