The COVID-19 pandemic has affected all societies worldwide. The heightened levels of stress that accompanied the crisis were also expected to affect parenting in many families. Since it is known that high levels of stress in the parenting domain can lead to a condition that has severe consequences for health and well-being, we examined whether the prevalence of parental burnout in 26 countries (9,923 parents; 75% mothers; mean age 40) increased during COVID-19 compared to few years before the pandemic. In most (but not all) countries, analyses showed a significant increase in the prevalence of parental burnout during the pandemic. The results further revealed that next to governmental measures (e.g., number of days locked down, homeschooling) and factors at the individual and family level (e.g., gender, number of children), parents in less (vs. more) indulgent countries suffered more from parental burnout. The findings suggest that stricter norms regarding their parenting roles and duties in general and during the pandemic in particular might have increased their levels of parental burnout.