This article focuses on the MID as an indirect tax support for acquiring one's housing. This form of support is the most widely used in the Czech Republic compared to other tax reliefs and causes the highest losses for government budgets. This paper provides quantitative evidence on how the MID was distributed among taxpayers in the Czech Republic in the period 2008-2019 in relation to their taxable income and revenue losses for government budgets and assesses the effectiveness of these tax measures in reducing socioeconomic inequalities among taxpayers. Research based on the application of the MID in tax returns has shown the effective distribution of the MID until 2017. Tax support for housing was used mainly by taxpayers with low taxable income, which is also the largest group. The essence of vertical equity was fulfilled, which contributed to reducing the level of social inequality. This positive distributional effect has diminished over time. As of 2019, the highest share of public expenditure was redistributed to taxpayers with higher taxable income, indicating the existence of inequalities in the tax system. The different developments over time have shown that the use of the mortgage interest deduction cannot be assessed statically, as it evolves dynamically over time.