The COVID-19 epidemic has had a debilitating effect on the health and wellbeing of the public worldwide. Restrictions on day to day activities and strict measures including the lockdown and social distancing measures were taken as a result of this pandemic, globally. The objective of this study was to examine how healthy eating behaviour, perceived behavioural control over eating and engagement in physical activity could also have been impacted by this pandemic. Stress and self-compassion are two main factors that have found to be associated with changes in health promoting behaviours from previous literature. The current study used a longitudinal design to examine the role of self-compassion in the relationship between stress and health behaviours in New Zealand residents. The results showed that stress acted as a mediating variable between self-compassion and eating behaviour during the lockdown (Alert Level 4) but this effect was not found post lockdown (Alert Level 2). However, participants who had higher levels of self-compassion were found to have better perceived behavioural control via the mediating role of stress, both during and post lockdown. This effect was not found for physical activity at both time points. This study also investigated the moderating role of self- compassion in the relationship between stress and changes in eating behaviour, perceived behavioural control and physical activity. No support was found for moderation. The findings of this study point towards the complicated nature of the interaction between these various variables. Future studies need to be undertaken to explore this interaction and use self- compassion interventions to gain a better understanding of the relationship between stress, self- compassion and health promoting behaviours.