We assessed linkages of mothers' emotion coaching and children's emotion regulation and emotion lability/negativity with children's adjustment in 72 mother–child dyads seeking treatment for oppositional defiant disorder (ODD). Dyads completed the questionnaires and discussed emotion‐related family events. Maternal emotion coaching was associated with children's emotion regulation, which in turn was related to higher mother‐reported adaptive skills, higher child‐reported internalizing symptoms, and lower child‐reported adjustment. When children were high in emotion lability/negativity, mothers' emotion coaching was associated with lower mother and child reports of externalizing behavior. Results suggest the role of emotion regulation and emotion lability in child awareness of socio‐emotional problems and support the potential of maternal emotion coaching as a protective factor for children with ODD, especially for those high in emotion lability.