Adverbs play a central role in structuring discourse, conveying speaker stance, and modifying propositional content. -Ly adverbs constitute up to 55% of common adverbs and are frequently used in academic prose. Attaining a nuanced grasp of adverbial usage in learner English, and of how closely Turkish learners’ patterns align with native-speaker norms, is crucial. In this regard, this paper examines the use of -ly adverbs by Turkish EFL learners of English in comparison to native speakers. The investigation relies on two corpora of novice academic English: The Turkish International Corpus of Learner English (TICLE) and the Louvain Corpus of Native English Essays (LOCNESS), and one corpus of expert academic English: BNC (British National Corpus), representing learner and native speaker writing. The frequencies, lexical choices, and the distribution of -ly adverbs were analyzed across three corpora. In addition, syntactic functions of the identified -ly adverbs were classified according to Quirk et al. (1985) and Hasselgård’s (2015) classifications. The analysis reveals that Turkish EFL learners rely on a narrower range of -ly adverbs, frequently using those associated with spoken rather than academic discourse, whereas native expert writers demonstrate a more varied and academically appropriate adverbial repertoire. Additionally, Turkish learners underuse most -ly adverb categories, particularly adjuncts and disjuncts, while overusing conjuncts and intensifiers. These findings highlight the gap between native and non-native academic writing, emphasizing the need for explicit instruction in the use of adverbials to develop a more advanced academic style.