While the threat that al-Shabaab poses to the West can easily be overstated, its outreach to Muslims living in Europe and the United States has been successful relative to other al-Qaeda-linked groups and warrants exploration. The organisation has recruited dozens of foreign fighters from the West (see Appendix). It also holds the dubious distinction of being the first jihadist organisation to recruit an American citizen to commit an act of suicide terrorism. Its recruitment strategy is therefore worthy of examination as a case study of how jihadist groups formulate strategies to lure Western Muslims. Through a combination of primary source analysis, background interviews in East Africa and an in-depth quantitative analysis of the group’s Twitter output, this paper aims to go beyond the simple statement of this problem by explaining how al-Shabaab markets itself to Muslims beyond its borders and what methods it employs. It also explores how the group is using social media to engage its followers in ways that other actors in the global jihad movement have not yet mastered.