Abstract
<jats:title>Abstract</jats:title> <jats:p> Extramural vocabulary learning is about informal learning of foreign or second language (L2) vocabulary outside (Lat. <jats:italic>extra</jats:italic> ) the walls (Lat. <jats:italic>murus</jats:italic> ) of the classroom. It is always self‐initiated and encompasses both incidental and intentional learning. Although not a new phenomenon per se, extramural vocabulary learning has gained traction in vocabulary research in the 2000s, and especially so regarding L2 English due to its status as a global language and dominance on the internet. However, extramural vocabulary learning can involve any target language, denoted extramural L <jats:sub>n</jats:sub> . This article discusses the key concept <jats:italic>extramural L</jats:italic> <jats:sub> <jats:italic>n</jats:italic> </jats:sub> and theoretical frameworks used in research and describes different research orientations, materials and methods used, and research findings about the relation between learners' engagement in various extramural L <jats:sub>n</jats:sub> activities (such as listening to music or playing video games) and vocabulary learning. Finally, the article addresses some critiques of this line of research. There are also suggestions for future research. </jats:p>