Parental reflective functioning describes the ability of a parent or caregiver to interpret their child’s behaviour as motivated by internal mental states different to their own, and to recognise how the parent and child’s mental states influence their interactions and relationship. More sophisticated reflective skills are associated with greater confidence in the parent/caregiver role, whilst poorer parental reflective functioning has been linked to higher levels of caregiver stress. Theory suggests that capabilities for parental reflective functioning develop in the context of the adult’s early relationships and attachment to their own parent. However, a ‘loose coupling’ exists between adult attachment style and parental reflective functioning, whereby insecure attachment is associated with poorer parental reflective functioning, yet the quality of parental reflective functioning is varied amongst securely attached individuals. This suggests that other factors, beyond attachment style, influence an individual’s level of parental reflective functioning. A systematic review was conducted to identify and evaluate existing research on psychological characteristics related to increased or reduced parental reflective functioning in healthy populations. Fourteen studies were identified encompassing four main areas of research: Personality; emotion regulation; parenting and executive function. Emotion regulation was the most frequently researched area, and emotion regulation difficulties were consistently associated with poorer parental reflective functioning. On the basis of these findings, and empirical study was conducted to examine the relationships between attachment dimensions, emotional dysregulation and PRF, and how these relate to caregiver stress amongst foster carers. Seventy-three foster carers participated in an online study assessing attachment, difficulties with emotion regulation, parental reflective functioning and caregiver stress. The results suggest that parental reflective functioning predicts caregiver stress, and that attachment dimensions and emotion regulation also have a role in this association. Overall, the results add to the existing literature attachment, emotion regulation and parental reflective functioning. Several areas for future research are identified, including ways in which interventions to improve parental reflective functioning could be improved.