More than half of mothers of children with ADHD have a lifetime history of major depressive disorder. Prior research has thus examined treatments integrating behavioral parent training (BPT) and cognitive-behavioral therapy (CBT) to target parent depressive symptoms that may contribute to negative parent/child behaviors. However, little is known about whether such interventions affect depressogenic cognitions of child behaviors and pathways by which these cognitions impact parenting. This study examined effects of the integrated parenting intervention for ADHD (IPI-A; a combination of group CBT for depression with BPT), and standard BPT on post-treatment child-blaming and child-crediting attributions, and maternal expectations of child compliance. We hypothesized that randomization to IPI-A would predict greater reductions in depressogenic cognitions of child behavior, relative to BPT. The current study also explored maternal attributions as mechanisms of change in observed parenting outcomes. Participants were 98 children (Mage = 8.78; 66% Male) with ADHD and their biological mothers with at least a mild level of depressive symptoms. Mothers in IPI-A reported significantly more post-treatment child-crediting attributions relative to those in BPT. Treatment group was not associated with post-treatment child-blaming attributions or expectations for child compliance. Exploratory mediation analyses demonstrated that post-treatment child-crediting attributions mediated the association between treatment condition and observed negative parenting at post-treatment. Specifically, mothers in IPI-A (vs. BPT) exhibited less negative parenting at post-treatment via more child-crediting attributions. These findings indicate that integrating CBT skills in BPT for child ADHD enhances outcomes on child-crediting attributions for mothers with elevated depressive symptoms.