Purpose <p>Brassinosteroids (BRs) have been shown to exert several beneficial effects in plants, including enhancing yield. Therefore, the aim of this study was to investigate the effects of 24-epibrassinolide (EBL) on <i>Mentha arvensis</i> and <i>Mentha</i> × <i>piperita.</i></p> Methods <p>Seedlings grown in a greenhouse were foliar-sprayed with five concentrations of EBL (0, 10^–8, 10^–7, 10^–6 and 10^–5&#xa0;M), followed by morphological and physiological analyses. <i>Results</i>: Species in the 10^–6&#xa0;M EBL group showed the highest plant height, fresh and dry herb yield, chlorophyll content, and essential oil content. Treatment with 10^–6&#xa0;M EBL maximized total phenolic content and essential oil yield in <i>M</i>. <i>arvensis</i> and enhanced the antioxidant activity of <i>M.</i> × <i>piperita</i>. Treatment with 10^–7&#xa0;M EBL increased the antioxidant activity of <i>M</i>. <i>arvensis</i> and upregulated total phenolic and essential oil contents in <i>M.</i> × <i>piperita</i>. GC–MS analysis identified 11 essential oil components in <i>M</i>. <i>arvensis</i> (mainly pulegone, isomenthone, menthone, and 1-octen-3-ol) and 15 components in <i>M.</i> × <i>piperita</i>, mainly menthol, menthofuran, and menthone. Increasing EBL concentrations reduced menthone and isomenthone levels in <i>M</i>. <i>arvensis</i>. Heatmap, canonical correlation, and Z-score analyses confirmed that 10^–6 and 10^–7&#xa0;M EBL significantly improved herb yield and antioxidant capacity.</p> Conclusion <p>Optimized EBL application enhances growth and secondary metabolite production in mint.</p>