In this dissertation, the effectiveness of subtitled audio-visual materials (videos, films, series) in second language learning is examined; and its theoretical background and related theories are reviewed, such as Krashen’s Acquisition-Learning Hypothesis and Input Hypothesis; Paivio’s dual coding theory; moreover, Oxford’s learning styles and strategies. Furthermore, previous studies in the field are introduced, through which benefits and limitations of subtitled materials in SLA are summarised. In addition, the paper describes a small-scale research – recently conducted with Hungarian university students – in which the results of two groups of students are compared: one watching a video with subtitles, and one watching it without them. The study provides evidence for the effectiveness of both subtitled and unsubtitled audio-visual materials in vocabulary learning/teaching. Furthermore, the research provides data about the attitude of Hungarian people towards the use of subtitled materials in SLA, which suggest that Hungarian people are generally positive about their usefulness, and they utilise – to varying extents – the language learning facilities provided by such resources.