Although data-driven learning (DDL) has gained considerable attention over the last 30 years, it is still under-researched in secondary education EFL settings. We address this gap by investigating the implementation of a “blended” DDL approach for the teaching of English modal verbs to high school students in Greece which involves students’ conducting online queries and working with handouts of printed concordances from various sources: a) an English course book corpus (ECCo) compiled specifically for our purposes, b) free-to-access materials from the Web, and c) the Corpus of Contemporary American English (COCA). We present the step-by-step application of DDL training sessions and DDL-based lessons on modal verbs, with a particular focus on the adaptation of existing textbook materials. We present students’ impressions of this treatment after each DDL session, as well as the implications of our study for further research and relevant pedagogical practice.