Melissa officinalis L. and Mentha spicata L. are widely used aromatic plants; however, variations in essential oil composition related to geographical origin may significantly influence their biological activities. The present study aimed to characterize the chemical composition and comparatively evaluate the antioxidant and antimicrobial properties of essential oils obtained from plants collected in the Settat region of Morocco. Essential oils were extracted by hydrodistillation and analyzed using GC–MS. Geraniol (30.37%), (Z)-2,6-octadien-1-ol (22.52%), and citronellol (13.54%) were the major constituents of M. officinalis oil, whereas (-)-carvone (58.05%) predominated in M. spicata oil, followed by trans-carveol (7.29%) and (R)-1-methyl-5-(1-methylethenyl)cyclohexene (5.45%). Antioxidant activity was assessed using DPPH, ABTS, and FRAP assays. M. spicata oil demonstrated stronger radical-scavenging activity in DPPH and ABTS assays, while M. officinalis showed higher ferric-reducing power. Antimicrobial activity was evaluated against Gram-positive and Gram-negative bacteria and one yeast strain. Both oils exhibited higher inhibitory effects against Staphylococcus aureus and Staphylococcus epidermidis compared with Pseudomonas aeruginosa. The obtained results demonstrate distinct compositional profiles of the essential oils, with dominant terpenoid constituents associated with the measured antioxidant and antimicrobial activities. The characterized chemical composition and corresponding bioactivities indicate their suitability for further consideration in pharmaceutical, food, and cosmetic applications.