This chapter reports on an empirical study with young EFL learners (12–15 years old), investigating the development of their competence in relation to processing and comprehending idioms through data-driven learning (DDL). Sixty young EFL learners were exposed to authentic non-concordance examples from a corpus before studying concordance lines and extended sentences as part of a 16-week programme of study. Data analysis of pre- and post-achievement tests on idioms showed significant improvement in participants’ overall ability to deduce idiomatic meaning from context. The chapter also includes relevant activities and practical guidance on how corpus-based activities and DDL can improve young EFL learners’ processing of idioms, which can prove helpful to EFL instructors and materials developers considering implementing data-driven learning with young EFL learners.