Background: Picky eating behaviors among children challenge nutritional intake and healthy development and place considerable stress on parents. Parenting approaches play a critical role in shaping young children’s dietary behaviors. Mindful parenting, which refers to parents responding to their child’s needs with awareness, acceptance, attention, and mindful discipline, has gained increasing attention. Parental dietary competence may determine whether mindful parenting effectively discourages picky eating behavior in children. Objectives: This study explored whether mindful parenting and parental dietary competence are associated with picky eating behaviors in young children. The mediating role of parental dietary competence in this association was also investigated. Methods: A total of 412 parents of children enrolled in six preschools across six administrative districts in New Taipei City, Taipei City, and Taoyuan City, Taiwan, were invited and recruited. Data were collected using three validated parent-reported instruments, including a mindful parenting scale, parental dietary competence scale, and children’s picky eating behaviors scale. Results: Mindful parenting influenced children’s picky eating behaviors through the full mediation of parental dietary competence. The identification of parental dietary competence as a mediator underscores the need for early preventive interventions and parenting education that integrate parental mindfulness and dietary competence to foster healthy eating habits from the outset of early childhood. Conclusions: Practical recommendations and future research directions are provided regarding mindful parenting, parental dietary competence, and picky eating behaviors in young children.