Previous studies have indicated that childhood adversity and emotional attachment difficulties are common in hoarding disorder. The aim of this cross-sectional study was to explore whether current insecure attachment style, operationalized as insecure attachment to romantic partners, and emotional over-attachment to objects might be one mechanism linking the experience of early adversity to later hoarding tendencies. Data was gathered using an online survey from 463 adult participants; n = 216 scored in the clinical range for hoarding. The experience of two types of childhood trauma (emotional abuse and physical neglect) predicted higher levels of hoarding symptoms. Attachment anxiety and avoidance were positively correlated with hoarding symptoms and with emotional attachment to possessions. Current attachment insecurity and emotional attachment to objects partly mediated the relationship between childhood trauma and hoarding symptoms, after controlling for anxiety and depression. This study provides evidence for a novel way by which traumatic life events may influence hoarding symptomatology via attachment to significant others and object attachment. The findings are limited by the use of a cross-sectional design; however, they support the growing body of research which points to the importance of early adverse events and attachment difficulties in the aetiology of hoarding.