Abstract
The 15‐item version of the Security Scale Questionnaire (SSQ), primarily capturing parent's safe haven support, is the most valid self‐report measure of attachment security for preadolescence. Recently, nine items assessing secure base support were added. This study aimed to further validate the 24‐item version of the SSQ by evaluating measurement invariance across three cultures, child gender and age, and mother‐child and father‐child relationships. This study also evaluated the SSQ's item‐level characteristics using item response theory (IRT). Participants were 1173 children 9–14 years old ( M ( SD )age = 11.29 [1.27]; 46.4% boys) from the United States, Italy, and Romania. The SSQ showed measurement invariance across the three countries, child gender and age, and mother‐child and father‐child relationships. Children rated mothers higher than fathers for safe haven support and rated both parents similarly for secure base support. Results underscore the SSQ's strong psychometric properties, the consistency of children's perceptions of secure attachment relationships across three cultural contexts, and the importance of evaluating attachment security with both parents.