In rapidly ageing European societies, measures promoting healthy ageing to relieve the pressure on countries' welfare systems become increasingly important. However, health inequalities in Europe are a reality, posing a serious risk on people's chances to age in a healthy way. This dissertation's objectives were to examine the social health inequalities in old age and assess the different life-course processes that may explain these health inequalities. Furthermore, following a comparative research approach, this dissertation studied whether there were differences in these health inequalities across welfare arrangements in the multiple European countries assessed. In conclusion, the findings evidence the long reach of childhood experiences and socioeconomic conditions to health in old age, while also showing that some of the unfavourable outcomes can be addressed throughout the life course. Furthermore, more generous welfare arrangements are shown to have an advantageous impact on socioeconomic health inequalities in old age.