Posttraumatic stress symptoms are prominent in the lives of parents of young children with substance use disorders (SUD). Parenting experiences, particularly stress and competence, impact parenting behaviors and concomitant child growth and development. Factors that promote positive experiences of parenting, such as parental reflective functioning (PRF), and protect the mother and child from negative outcomes are crucial to understand to develop effective therapeutic interventions. The current US study analyzed baseline data from a parenting intervention evaluation to examine how length of substance misuse, PRF, and trauma symptoms were associated with parenting stress and parenting sense of competence among mothers in treatment for SUDs. Measures included the Addiction Severity Index, PTSD Symptom Scale-Self Report, Parental Reflective Functioning Questionnaire, Parenting Stress Index/Short Form, and Parenting Sense of Competence Scale. The sample included 54 predominantly White mothers with SUDs who had young children. Two multivariate regression analyses found that (1) lower parental reflective functioning and higher posttraumatic stress symptoms were associated with higher parenting stress, and (2) only higher posttraumatic stress symptoms were associated with lower levels of parenting sense of competence. Findings underscore the importance of addressing trauma symptoms and PRF when aiming to improve parenting experiences for women with an SUD.