The study contributes to the literature on private supplementary tutoring by shedding light on this phenomenon in the Czech Republic. The aim of the paper is to identify the reasons for seeking out private supplementary tutoring and to assess the factors underlying its demand. In the representative sample of 1,265 senior upper-secondary school students from two distinct regions of the Czech Republic, 37% acknowledged participation in private tutoring lessons (provided by individuals) and 10% reported enrollment in preparatory courses for university admission (organized by institutions) during their upper-secondary studies. It seems that both enrollment in different educational tracks and specific school subjects are associated with different reasons for taking private tutoring lessons. The results of binary logistic regression suggest that the mother's educational attainment, family income, students' academic performance, residence in the capital city, and female gender are significant predictors of students' enrollment and participation in the explored private tutoring activities. These findings confirm the strong influence of family background on educational attainment identified in previous Czech social-stratification research. In a wider European context, the patterns of private supplementary tutoring resemble those in neighboring countries.