Harmonized Irish Longitudinal Study on Ageing (Harmonized TILDA) is an easy-to-use version of data from the first 2 waves of the Irish Longitudinal Study on Ageing (TILDA) with a set of harmonized variables suitable for cross-country analysis. Using the RAND HRS and Harmonized HRS as models, Harmonized TILDA 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 TILDA, including a description of its creation, the TILDA variables used, and descriptive statistics, is detailed in the Harmonized TILDA codebook.