This thesis deals with the phenomenon of volunteer engagement. A thorough discussion of different terms used in German such as Freiwilliges Engagement (volunteer engagement), volunteer work, Bürgerschaftliches/Zivilgesellschaftliches Engagement (civic engagement) and Ehrenamtliches Engagement (honorary engagement) is followed by an analysis of the characteristics of these terms using a multidimensional model. The social and legal framework of volunteer engagement are discussed locating volunteer engagement on the macro and meso levels of society, analysing cooperative relationships with other areas of society, clarifying the legal framework, outlining the landscape of the organisation of the third sector as well as presenting results from empirical research on the structure and volume of volunteer engagement. Another chapter is dedicated to informal learning processes in volunteer engagement settings. Using the dimensions place and setting, process and learning content, some light is shed on this particular facet of volunteer engagement. Based on the literature available, an empirical study was conducted to investigate the structure and volume of volunteer engagement at VinziWerke Eggenberg focusing on the skill acquisition of volunteers. To this purpose, a standardised survey was carried out. The results show that most of the respondents from VinziWerke are female as well as highly educated and that the majority is over 50. They mainly get involved for altruistic reasons, but egoistic reasons play a role, too. The respondents volunteer engagement is also characterised by the fact that it is relatively time-consuming. As far as skill acquisition is concerned, most respondents do not think that it relates to their volunteer engagement. However, some of the respondents state that volunteer engagement allowed them to develop individual skills.