This qualitative case study investigated how adult ESL students in a postsecondary English for academic purposes (EAP) program in the Southwest region of the United States experienced The Big Bang Theory (TBBT) television sitcom as a source of humorous authentic teaching materials. Krashen's (1982) affective filter hypothesis served as the theoretical framework to explore 12 participants' experiences in terms of the affective factors of anxiety, self-confidence, and motivation. Corpus linguistics analysis revealed that 3.96% of all words spoken on the pilot episode of TBBT occurred more frequently in the academic writing section of the Corpus of Contemporary American English database compared to only 0.25% on the words in the pilot episode of Modern Family. These findings suggested the potential suitability of TBBT for use in EAP contexts to expose students to target academic vocabulary and content in a low-filter environment. Semi-structured interviews, observations, and interview guides revealed that TBBT reduced students' affective filters due to its inclusion of humor, authentic language, different communication styles, and different personality types. In contrast, participants reported that TBBT could increase students' affective filters due the show's rapid speed of dialogue, inclusion of potentially inappropriate topics or humor, or its unfamiliar words and content. With proper excerpt selection and preparation, these findings suggested that TBBT could be used to reduce postsecondary EAP students' affective filters. Further research is needed to understand how the use of TBBT may influence learning outcomes in EAP contexts.