Psychological First Aid is a brief intervention based on international guidance from the World Health Organisation. Free to access online training in the intervention was introduced during the COVID-19 pandemic in UK. We aimed to determine the uptake of Psychological First Aid training among healthcare workers in care homes in the UK and to assess its effects on their wellbeing. This was a sequential mixed methods design. Healthcare workers (nurses and carers) working in care homes in the UK were surveyed about their uptake of Psychological First Aid, their stress, coping efficacy and the key concepts of Psychological First Aid (safety, calmness, hopefulness, connectedness, and accomplishment). Those that completed the Psychological First Aid training were asked to share their experiences via qualitative survey. Data collection was conducted between June and October 2021. Analyses included descriptive statistics and regression analysis. A six step thematic analysis was used to interpret the qualitative data. 388 participants responded to the survey. The uptake of Psychological First Aid training was 37 (9.5%). Psychological first aid was a significant predictor for coping efficacy (β = 17.54, p = .001). Participants with a physical or mental health condition experienced higher stress and lower coping regardless of PFA training. Four themes were identified from the qualitative analysis: self-awareness and growth, relationships with others, overcoming stress and accessibility. While this study suggests some benefits to healthcare workers in care home settings undergoing PFA the poor uptake of the training warrants further investigation. Care home staff need psychological support. This gap remains as few completed PFA training. This is the first study in UK and worldwide to look at the effects of psychological first aid on stress and coping in this population and it warrants further investigation.