Quality factors are the subject of increasing interest in the research and practice of early childhood education and care (ECEC). The purpose of the article is to emphasize the importance of the children's voice in relation to the quality of ECEC. This article focuses on children's negative experiences of ECEC as they can be used to improve services and increase children's wellbeing. The data was collected by means of a questionnaire from 2500 children aged 2-6 years (girls 50.4%) in Finland. The data was analysed using qualitative and quantitative content analysis. According to the results, children mentioned both structural and process factors. Peer interaction among children was mentioned the most when referring to negative experiences in ECEC. We conclude that children's negative experiences provide an opportunity for ECEC professionals to support children's resilience and a sense of belonging, which are important elements in the process quality of ECEC.