This paper examines self-legitimation in selected speeches of Abubakar Shekau, the longest-serving leader of Boko Haram terrorists (BHT). The article analyses seven of the speeches Shekau delivered during his reign as the BHT leader between 2009 and 2021, using f4analyse as a coding tool and Theo van Leeuwen’s (2008. Discourse and practice: New tools for critical discourse analysis) Discourse Legitimation approach to discourse analysis. The analysis discloses that Shekau uses three legitimation strategies: authorisation, moralisation and rationalisation to justify the actions and practices of BHT. The three legitimation strategies are linguistically realised through positive self-presentation strategy by engaging in self-glorification, personalising and collectivising victory, and claiming and announcing success to legitimate the mission of the group in carrying out the struggle. The strategies are deployed to positively present Abubakar Shekau as fighting a legitimate struggle.