We investigated the context role of family factors in obsessive compulsive disorder (OCD) by comparing observed parent-child interaction behaviors of OCD and non-clinical families during three parent-child discussion tasks. We examined whether behaviors differentiating groups would be consistent across all discussions, or present only during specific tasks. We also investigated the effect of family-based cognitive behavior therapy on parent-child interactions and aimed to identify interaction behaviors associated with OCD symptom change. Thirty-nine children and adolescents (9-16 years old) and their parents participated in three discussion tasks about: (1) pleasant, (2) anxiety-provoking, and (3) conflict situations. Groups were compared on observer-rated parent and child behaviors. OCD dyads participated in discussions again after treatment. Results supported task-specific hypotheses for parent-child interactions in OCD, except for child warmth, demonstrating effects in the expected direction across all discussions. OCD and control families were distinguished on both child and parent behaviors, particularly during the anxiety discussion. Children and adolescents with OCD showed less warmth, confidence, positive problem-solving, and responsibility, and more doubt compared to controls. OCD group parents showed less warmth, confidence, and positive problem-solving, and more doubt and enhanced responsibility than controls. Treatment effects were present for the anxiety discussion exclusively. Pre-post reduction in OCD symptom severity was significantly correlated with an increase in child responsibility, likely related to a reduction in unhelpful avoidance behaviors targeted in treatment. Outcomes support models of OCD maintenance highlighting the importance of family environment factors in OCD symptoms, suggesting that parent-child interaction behaviors characterizing OCD families are contextual.