This study assessed the associations between maternal reflective functioning and progressive parenting beliefs and their association with nurturing parenting and preschool children’s emotion understanding. Mothers (N = 52) reported on their parenting beliefs and nurturing parenting. Mothers were interviewed using the Parent Development Interview-Revised to assess reflective functioning. Preschool-aged children (between 3 and 5 years old) completed a perspective-taking task assessing emotion understanding. Mothers with higher levels of reflective functioning had more progressive parenting beliefs and had children with more advanced emotion understanding. Mothers with more progressive parenting beliefs reported more nurturing parenting. These findings indicate that both parenting beliefs and reflective functioning are important predictors of both parenting behavior and young children’s emotion understanding and may be important targets for clinicians working to improve outcomes for families.