Perinatal loss from all causes is a common occurrence and can have a profound impact on parents’ psychological wellbeing. In 2021, NHS Maternal Mental Health Services were launched in part to support those with early bereavement. However, there remains some uncertainty regarding the selection of appropriate treatment approaches for parents. Furthermore, partners risk exclusion from accessing support, as less is known about the prevalence of difficulties among this population. This thesis comprises of two parts. Part A presents an empirical investigation on the prospective impact of perinatal loss on recently bereaved partners, assessed at two time points, six months apart. The results supported a heterogenous profile of grieving, although there remained evidence of clinically significant grief and depression for a substantial proportion of the sample at T1 and at follow-up. Additionally, avoidant coping, experience of stillbirth, female gender, and younger age appear to be factors associated with more severe outcomes. Part B examines Acceptance and Commitment Therapy (ACT) as a potential, yet empirically untested, treatment modality for providing psychological support to parents experiencing perinatal loss. This is achieved via a conceptual review, mapping key factors documented in the literature associated with perinatal grief onto the model’s six core processes. The findings suggest that ACT may be a suitable treatment model for addressing perinatal grief, through enabling greater psychological flexibility, which may help parents to personally connect with the significance of the loss and plot a way forward. It is argued that this approach may be especially pertinent in social contexts characterised by silence and invalidation around perinatal loss, tackling avoidance processes which have been associated with a range of mental health difficulties. Implications and recommendations for future research are discussed.