People's choices and life trajectories have changed considerably in recent decades resulting in more complex life course and family dynamics. In turn, these changes have raised important societal and scientific challenges regarding low fertility, gender equality, work-life balance, and uncertainty (among others). Data from the second round of the Generations and Gender Survey (GGS-II) provides key information to address these pressing societal and scientific challenges. GGS-II is a longitudinal survey that collects information on individuals between the age of 18 to 79 and covers a wide range of topics, such as union formation, family and partnership histories, household dynamics, work, wellbeing and gender role attitudes. As such, the GGS-II represents a valuable data resource that can aid researchers and policy makers in conducting advanced empirical research and developing evidence-based policies on family, fertility and gender. This paper focuses on the baseline wave (wave 1) of the GGS-II. It demonstrates the uniqueness of GGS-II in terms of the wide geographical coverage and a mixed-mode of data collection, as well as the innovations in the survey content of the baseline questionnaire.