Behavioral parent training is an evidence-based intervention for children with attention-deficit/hyperactivity disorder (ADHD), but knowledge on the differential effects of behavioral techniques for specific subgroups of children is very limited. Attachment representations of children with ADHD may affect how receptive children are to changes in parenting. In this study, we investigated whether specific behavioral techniques were more or less effective for children with ADHD in relation to their attachment representations. We included parents of 74 children with ADHD (4–11 years, M = 8.15) who took part in a larger randomized controlled microtrial in which they were randomized to a two session training in antecedent-based techniques (i.e., stimulus control techniques: rules, instructions; n = 26), a two session training in consequent-based techniques (i.e., contingency management techniques: praise, rewards, ignoring; n = 25) or a waitlist control condition (n = 23). We examined whether attachment representation moderated the effectiveness of a) training versus waitlist, and b) antecedent- versus consequent-based techniques. Attachment representations were measured with a story stem task, the intervention outcome was daily parent-rated problem behaviors of the children. Attachment representation did not moderate the effects of the training compared to the waitlist. However, compared to antecedent-based techniques, consequent-based techniques were less effective for more securely and less disorganized attached children, and particularly effective for more disorganized attached children. This was the first study examining attachment as a moderator of behavioral techniques for ADHD. If replicated, the findings of this study can be used for treatment development and tailoring.