The Turning Points of the Life Course (TPLC) follow-up survey, carried out by the Hungarian Demographic Research Institute between 2001 and 2017, involved 16,363 respondents aged 18–75 at baseline, of whom 6,315 completed all five waves. The study was launched to document and analyse post-1990 demographic shifts in Hungary, such as declining fertility, delayed childbearing, the rise of unmarried cohabitation, as well as the social and economic context of these changes. The survey combined retrospective and prospective data to capture past life course events and future intentions. It was guided by theories of economic crisis, the second demographic transition, and social anomie. The longitudinal design of the study enabled causal analyses of how structural conditions, values, and attitudes shape demographic behaviour, going beyond the limitations of cross-sectional surveys.From the second wave onwards, the TPLC was incorporated into the international Generations and Gender Survey (GGS), adopting its core questionnaire while retaining country-specific modules. The use of a stratified sampling method, systematic respondent tracking, and a gradual shift from paper-based to computer-assisted interviewing ensured the high quality of the data. Despite attrition, panel stability remained comparatively strong, with nearly 40% of the initial sample retained after 15 years.The English-language longitudinal database contains around 7,000 variables relating to fertility, partnerships, households, work, education, income, health, ageing, values, and attitudes. Alongside detailed metadata and questionnaires, the database is a valuable resource for studying life-course trajectories in Hungary, as well as for cross-national demographic research within the GGP framework. The longitudinal dataset for the five waves of the TPLC is available via the Generations and Gender Programme (GGP) website (www.ggp-i.org) after registration and completion of the application form, along with the required supporting documents. Once the application has been approved, the requested data can be downloaded electronically in SPSS and Stata formats. The English documentation for the five waves of the TPLC survey can be found on the websites of GGP and the Hungarian Demographic Research Institute. User Guide for the data is available here: https://doi.org/10.21543/WP.2025.42