Long noncoding RNAs (lncRNAs) have emerged as important regulators of gene expression in plants. They have been linked to a wide range of molecular mechanisms, including epigenetics, miRNA activity, RNA processing and translation, and protein localization or stability. In Arabidopsis, characterized lncRNAs have been implicated in several physiological contexts, including plant development and the response to the environment. Here we searched for lncRNA loci located nearby key genes involved in root development and identified the lncRNA ARES ( AUXIN REGULATOR ELEMENT DOWNSTREAM SOLITARYROOT ) downstream of the lateral root master gene IAA14/SOLITARYROOT ( SLR ). Although ARES and IAA14 are co‐regulated during development, the knockdown and knockout of ARES did not affect IAA14 expression. However, in response to exogenous auxin, ARES knockdown impairs the induction of its other neighboring gene encoding the transcription factor NF‐YB3. Furthermore, knockdown/out of ARES results in a root developmental phenotype in control conditions. Accordingly, a transcriptomic analysis revealed that a subset of ARF7 ‐dependent genes is deregulated. Altogether, our results hint at the lncRNA ARES as a novel regulator of the auxin response governing lateral root development, likely by modulating gene expression in trans .