Shadow education (various forms or types of private supplementary tutoring) and its implications and determinants have been explored by the scholarly literature, yet gaps remain in the understanding of its complex relationships with mainstream schooling in various national settings. This study reduces one of these gaps by scrutinising the role of parental dissatisfaction, exploring which aspects of schooling make dissatisfied parents consider procuring private supplementary tutoring for their children. Data for the qualitative study were gathered through individual, semistructured, in-depth interviews with 65 Czech parents. A maximum-variation sampling strategy was employed to gain insights from parents with different backgrounds and life situations. Parents who sought private tutoring because of their dissatisfaction with schooling listed a large array of school-related causes that triggered their decision. These were related to classroom instruction (e.g., inappropriate curriculum, grade inflation in student assessment), classroom organisation (e.g., unfavourable disciplinary climate and classroom composition), school communication (e.g., late teacher feedback on students' performance) and general school culture (e.g., unfavourable student-teacher relationships). The study has implications for teachers, schools and relatedly also policymakers by showing how their (in)actions and ignorance towards the quality of the service they offer may nurture the demand for private tutoring, which in turn may undermine their efforts to mitigate educational inequalities.