The health and productivity of broiler chickens are related to their intestinal microbiota, which may be influenced by supplemented feed components. This trial intended to evaluate the effects of a dietary mixture of essential oils from oregano (Origanum vulgare ssp. hirtum), sage (Salvia triloba L.), and lavender (Lavandula angustifolia L.) on broiler chicken growth performance, intestinal microbiota, intestinal morphology, and meat chemical composition and oxidative stability. A total of 288 one-day-old male Ross-308 chicks were randomly assigned to four treatments with six replicate pens (12 chicks per pen). The chicks of the control treatment were fed typical commercial maize and soybean meal rations in mash form. The rations of the other three treatments were supplemented with a mixture of essential oils at 100, 200, and 400 mg/kg, respectively. At the end of the trial (day 42), tissue samples were collected for analysis. Major bioactive components of the three essential oils were identified by gas chromatography-mass spectrometry. Essential oil supplementation increased the radical scavenging capacity and the total phenolic content of the feeds. Performance parameters (weight gain, feed intake, feed conversion ratio, European production efficiency factor) were not affected significantly by the supplementation. Intestinal microflora populations (determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry) were modified significantly in both the cecum and the jejunum. Breast and thigh meat oxidative stability under refrigerated storage was improved significantly. Additional research is required to elucidate the potential synergistic effects of dietary mixtures of essential oils.