Children’s social information processing (SIP) encompasses cognitive and behavioral sequence that underlies social responses. SIP in peer interactions is well studied. Less is known about SIP in mother-child interchanges. Youth who show one SIP pattern a hostile attribution of intent (HAI) bias—in peer interactions consistently exhibit externalizing symptoms. This relationship is less consistently observed for HAI biases toward mothers. I hypothesized that this inconsistent association reflects moderating factors; specifically, engaging in foundational parenting practices (monitoring/supervision, consistent discipline) would weaken the relationship between HAI biases toward mothers and externalizing behaviors. Logistic regression yielded limited support for hypotheses. Consistent discipline predicted externalizing behaviors in some contexts; however, moderator effects were not detected. Isolated parenting practices thus may not buffer against the risk of externalizing behaviors linked to HAI biases toward mothers. Future research might examine how different HAI biases (peer, mother, etc.) related to each other and outcome variables.