Since late 2012, early 2013 Belgium has been one of Europe's main suppliers of foreign fighters to the war in Syria and later Iraq. A staggering number of over 600 foreign fighters has left Belgium since the war started. There are three main networks involved: Sharia4Belgium, Resto du Tawheed and the cell around Jihadi recruiter Khalid Zerkani. In this text, we will deal with the history of Jihadist activities in Belgium, look for demographical and sociological explanations on why Belgium seems to be a main supplier world-wide, a detailed overview of the recruiting groups will be provided, and we will zoom into a few of the personal motivations on why these young men and women left Belgium to join The Islamic State. In a separate paragraph, we will look into the involvement of Belgian foreign fighters in the attacks on Paris and Brussels in November 2015 and March 2016.