Newspaper political cartoons, known for their satirical nature, employ semiotic and linguistic techniques to comment on or criticise political leaders and events humorously. While previous studies on Nigerian newspaper political cartoons have focused on ideological issues and discourse frames, little attention has been given to the linguistic investigation of semiotic humour techniques in these cartoons. This study, therefore, investigates these humour techniques, utilising Salvatore Attardo and Victor Raskin's General Theory of Verbal Humour (GTVH) as the framework within a descriptive design. Three newspapers - Punch, The Guardian, and Daily Trust - were purposively selected for their regular publication of cartoons, criticising Nigeria's politics. Eleven political cartoons were purposively selected for their semiotic and humorous depictions of Nigeria's politics, and subjected to linguistic analysis. Six semiotic humour techniques were identified in the cartoons: exaggeration, humorous metaphor, distortion of formulaic expressions, neologism, innovative collocation, and sarcasm. These techniques were employed to satirise three governance issues in Nigeria - misgovernance, corruption and insecurity.