This article identifies patterns and trends within "Key Concepts in ELT", both since the inception of the feature in ELT Journal in 1993 and during the 17 years of the current editorship. After outlining the aims of the series, the article identifies key themes that have emerged over time, exploring the links between "Key Concepts" pieces and the trends and developments in ELT more generally. It finds that although earlier articles tended to focus on "teaching", "learning", and "language", more recent pieces have examined issues surrounding "teachers", "learners", and the "social context" of ELT. The article then considers the "reach", readership, and potential relevance of "Key Concepts" to debates and practices within ELT, drawing upon publisher records of ELT Journal's most accessed articles online and most cited articles, and concludes with a discussion of possible future directions for the series.