Aromatic plants have been used since ancient times for their medicinal properties, including potent antimicrobial activity. Strong evidence indicates that plant extracts, in general, and essential oils (EOs), in particular, can act as effective antimicrobial agents against a wide spectrum of pathogenic microorganisms. However, their poor water solubility and stability, as well as their high volatility, make the administration of EOs to achieve the desired therapeutic effects particularly challenging. Therefore, these features severely limit the application of EOs in the pharmaceutical field. In this context, nanotechnology-based strategies for developing nano-scaled carriers for the efficient delivery of EOs might offer potential solutions. In particular, considering the lipophilic nature of EOs, lipid-based nanocarriers represent the most suitable vehicles for the effective encapsulation and delivery of EOs. This chapter provides an overview of the different chemical compositions due to various endogenous and/or exogenous factors of a selection of oils and the most recent lipid-based encapsulation strategies to enhance their antimicrobial activity and promote their pharmaceutical application.