Background: There has been extensive research on the well-being of teachers, with much of it focusing on stress and mental health problems. Recent research has led to the development of the well-being process model, which examines predictors of positive and negative well-being outcomes. Research is now required to examine this model's applicability to teachers and those who communicate in languages other than English. Well-being has also been reduced by social isolation associated with COVID-19, and it is essential to investigate the causes of this reduced well-being.
 Aims: The present study had three main aims. First, to examine the applicability of the well-being process model to teachers. Secondly, to investigate a sample where teaching was in the Welsh language. Finally, to examine the response to the COVID-19 lockdown in this group and identify predictors of current and long term well-being.
 Methodology: The research was approved by the ethics committee, School of Psychology, Cardiff University, and carried out with the informed consent of the volunteers (67 staff from a Welsh-medium secondary school; mean age 36.8 years, range 19-53 years; 71% female). An online survey was carried out, and regressions conducted to examine associations between the well-being process predictor variables and the well-being outcomes. Predictors of current and long term well-being were also examined.
 Results: Thirty-six per cent of the sample reported high stress levels, but clinically significant anxiety and depression levels were low (7.2% anxiety; 4.4% depression). Positive well-being was predicted by high scores for psychological capital, social support, positive coping and low scores for negative work characteristics. Negative well-being was predicted by high negative work characteristics and negative coping, and low psychological capital scores. Current and long term COVID-19-related well-being was predicted by fear of infection and the stress of isolation.
 Conclusion: The results confirmed the applicability of the well-being process model to Welsh secondary school staff. Lockdown during COVID-19 affected well-being, with the risk of infection and the stress of isolation being the major influences.