Harakat al-Shabaab al-Mujahideen has proven itself to be a highly adaptable organisation. Their most recent evolution has seen them transform from an overt, military and governmental force in southern Somalia to a covert, insurgent and anarchic force in Kenya. This article indicates how al-Shabaab has reinvented itself in Kenya. Both ‘clan’ and ‘Islam’ are often thought of as immutable factors in al-Shabaab's make-up, but here we show that the organisation is pragmatic in its handling of clan relations and of Islamic theology. The movement is now able to exploit the social and economic exclusion of Kenyan Muslim communities in order to draw them into insurgency, recruiting Kenyans to its banner. Recent al-Shabaab attacks in Kenya, launched since June 2014, indicate how potent and dangerous their insurgency has become in the borderlands and coastal districts where Kenya's Islamic population predominates.