Is oppositional defiant disorder due to bad parenting?

No: Oppositional defiant disorder is associated with genetic and environmental factors which can include family stress, lack of supervision, trauma, and more recently chemical imbalance in the brain. It appears that many factors contribute and none are clearly causal. Treatment is best accomplished with a plan that involves parents as part of the therapeutic team. They should not feel guilt

Parenting and ODD: According to the DSM (manual for diagnosing psychiatric disorders) "children with oppositional defiant disorder may have experienced...hostile parenting..[but] impossible to determine if the child’s behavior caused the parents to act in a more hostile manner toward the child, if the parents’ hostility led to the child’s problematic behavior, or if there was some combination.