Parents often try to hide their negative emotions from their kids, hoping to protect them from experiencing adverse responses. However, suppression has been linked with poor social interactions. Suppression may be particularly damaging in the context of parent-child relationships because it may hinder parents' ability to support children's emotion regulation. Immediately after completing a stressful task, 109 parents of 7 to 11 year olds were randomly assigned to a suppression condition or a control condition during an interaction with their child. Children were given a set of instructions with pictures to build a Lego house and told to verbally instruct their parent without touching the Legos themselves. Trained research assistants coded parents' and children's positive and negative mood, responsiveness, warmth, parents' guidance, and the quality of the interaction. We found that suppression decreased parents' observed positive mood, responsiveness, warmth, and guidance, as well as children's observed positive mood, responsiveness, and warmth, and decreased the overall dyadic interaction quality. However, parent sex played a significant role in moderating these effects. Fathers in the suppression condition were less responsive and warm than control fathers, though children interacting with their fathers did not exhibit decrements in responsiveness or warmth. In contrast, children of suppressing mothers appeared less warm than children of mothers in the control condition, though suppressing mothers did not exhibit decrements in their observed warmth or responsiveness relative to control mothers. Taken together, these findings suggest that the desire to hide one's feelings from one's children may have unwanted negative consequences but may differ for fathers versus mothers. (PsycINFO Database Record (c) 2018 APA, all rights reserved).