The current study investigated whether teachers' years of working experience and their initial level of mindfulness, self-care, stress, and emotional exhaustion moderated the effects of a self-care- and mindfulness-based seminar on their stress and emotional exhaustion using a repeated measures design. The analyses of the data from 122 primary, secondary, vocational, and special school teachers (83% female) revealed comparably larger positive effects for teachers with lower initial self-care and mindfulness and higher initial stress and exhaustion levels. However, positive effects were detected across all groups of teachers, indicating mindfulness and self-care to be resources for promoting teachers' mental health. • The self-care and mindfulness seminar had positive effects on teachers' mental health. • Comparably larger effects were found for teachers with initially higher levels of stress and exhaustion. • Comparably larger effects were found for teachers with initially lower levels of mindfulness and self-care. • Teachers with better mindfulness, self-care, stress and exhaustion prerequisites also profited from the seminar. • Teachers' years of working experience had no significant moderating impact on the seminar's effectiveness. [ABSTRACT FROM AUTHOR]