This article estimates the effects of age, birth cohort, and survey year on income and consumption inequality in Korea using the Household Income and Expenditure Survey from 1990 to 2022. According to the results, inequality increases with age, and in particular, in the case of income, this age effect becomes larger as people become older. This is because, unlike developed countries with mature pension systems, inequality in Korea has actually increased due to the large number of people who have no or minimal pension after retirement. The effect of birth cohort on consumption inequality is U-shaped, showing a downward trend in inequality up to the birth cohort in the 1970s and the opposite trend thereafter. It is found that inequality among the children’s generation increases as the parents’ generation, which accumulated wealth through a period of rapid growth, increases gifts to their children. Furthermore, I estimate the inequality effects of major macroeconomic variables while controlling for these three time-related variables. In the case of income, the unemployment rate increases inequality and the employment growth rate decreases. The effect of opening to the outside world is that trade increases inequality, but foreign direct investment has the opposite effect of inflow and outflow. Variables related to financial development and income redistribution was all found to have lowered inequality. These effects all depend on age and appear to increase with age.