The sociology of education on the Czech Republic has focused almost entirely on relative measures of inequality (based on odds ratio data) than to trends in educational mobility (based on mobility tables). Therefore, there is a significant gap in our knowledge of how the Czech education system has evolved in the long term. Although the periods before and after the onset of socialism appear to have had very specific mobility patterns, we know relatively little about their differences. Therefore, this article attempts 1) to verify the findings to date about the character and extent of educational inequalities in the Czech half of socialist Czechoslovakia, and 2) to update these findings with a new mobility analysis. In this context the article poses two key questions: In what ways are the two mobility systems (pre-socialist and socialist) different? Was the Czech education system becoming more or less open? Using the mobility perspective and log-linear modelling, the analysis identifies some specific structural contexts and shows that the level of intergenerational educational reproduction that existed between 1906 and 1938 gradually diminished thereafter, except among women, who experienced a re-strengthening after 1948. Although after the Prague Spring in 1968 the association between the education of parents and their children began to strengthen, the mother-daughter association in educational reproduction weakened at the end of socialism.