Harmonized Korean Longitudinal Study of Aging is an easy-to-use version of data from eight waves of the Korean Longitudinal Study of Aging (KLoSA) with a set of harmonized variables suitable for cross-country analysis. Using the RAND HRS and Harmonized HRS as models, Harmonized KLoSA defines variables as identically as possible with the RAND HRS and Harmonized HRS to allow users to compare variables with all other Harmonized data sets. Documentation for each variable in Harmonized KLoSA, including a description of its creation, the KLoSA variables used, and descriptive statistics, is detailed in the Harmonized KLoSA codebook.