Introduction: This research aims to determine what makes children feel happy and unhapy at school, the determinants of their subjective well-being, and by using this information it attempts to develop recommendations for the ongoing process which is characterized by uncertainty and stress and for education due to the crisis created by COVID-19 and some implications for future research. Methods: This is a qualitative study using a phenomenological approach. The study group of the research consists of 34 primary school students in the 3rd and 4th grades (between the ages of 8-11) during the first term of 2019-2020 school year. A semi-structured interview form including three open-ended questions was used as data collection instrument. The data were analysed with descriptive analysis technique. Results: As a result of the study, the main determinants of children's happiness were found as the relationships which they established with their friends and teachers and their academic achievement. Also, it was revealed that students made references to creating more time for courses such as physical education, music, art, etc. and more free time at school and renewal of school fixtures in order to contribute to their happiness. Discussion: Considering the students' opinions about what makes them happy/unhappy at school and the factors that can contribute to their happiness, it can be argued that what is important for children's happiness at school is their relationships with their friends and teachers. This finding of the research has itself an utmost importance in the current process which the children experience either limited or no relationship with their peers and teachers due to the COVID-19 crisis. Accordingly, this research discusses the children's happiness within the framework of the researches that prompt us to rethink about students' happiness in an atmosphere of stress and uncertainty. Limitations: Although the qualitative method used in this study provided a profound picture of the views of students about what makes them happy/unhappy at the school, its limited sample constitutes an impediment to generalize it to all students in Turkey and the whole participants of the research. Conclusions: Considering what makes students happy and unhappy in schools in that research, we can argue that even the existence of schools alone, as the main grounds of social relationships, can be considered as a means of happiness in the current process. Nevertheless, future research should aim to determine what makes children happy in a process which the students are deprived of all facilities which the schools provided.