Children today encounter English in various contexts, with cartoons serving as a particularly influential medium. Beyond their entertainment value, cartoons also promote incidental foreign language acquisition. This article presents the findings of a study involving 240 sixth-grade pupils from Slovenian primary schools. Employing a quantitative approach, the study utilised both a questionnaire and a knowledge test to explore the relationship between English cartoon viewing and incidental vocabulary acquisition. It examined the frequency of cartoon viewing, pupils’ attitudes towards English-language cartoons, and the impact of subtitles on vocabulary test performance. The results indicate that a higher frequency of cartoon viewing, positive attitudes towards English cartoons, and the use of English subtitles are significantly associated with enhanced English vocabulary knowledge. The findings underscore the educational value of English cartoons in supporting vocabulary development and highlight the potential of engaging multimedia content in fostering incidental vocabulary acquisition in both classroom settings and out-of-school contexts. Consequently, educators should incorporate cartoon-based materials to enhance vocabulary learning, introduce authentic language exposure, and provide multi-sensory experiences tailored to varying learner preferences and proficiency levels.