Utilising a sequential explanatory mixed-methods approach, the current case study investigates the characteristics and frequency of the usage of verbal humour that positively or negatively affects the Saudi English as a Foreign Language (EFL) tertiary-level students across two different English language proficiency levels. The participants included 42 EFL teachers and 138 male EFL students from the English Language Institute (ELI) in King Abdulaziz University. The students were enrolled in the beginners (E101) and intermediate (E104) English language proficiency levels. The mixed-methods approach was implemented using audio and video recordings and a questionnaire as the data collection instruments. The findings stated the four main characteristics of both positive and negative verbal humours in Saudi EFL classrooms. These findings revealed that humour was more frequently used at the intermediate than at the beginner level, and that the most effective forms of humour at both levels involved language play, irony, jokes, and self-defeating humour. Suggestions, recommendations, pedagogical implications have also been presented.