Lip augmentation has become a key component in addressing cosmetic concerns in dermatology practice today. In particular, hyaluronic acid (HA) fillers are increasingly used for this minimally invasive procedure. In order to achieve the optimal cosmetic and aesthetic outcome, a fundamental understanding of the relevant anatomic components is necessary: this article details lip topography, muscular and subcutaneous organization, and pertinent vascular structures of the lip, while also highlighting important changes that occur with aging. In addition to understanding the disposition of HA fillers, we also discuss specific injection techniques commonly used in practice. Finally, injection of HA fillers is not without complications; physicians must be knowledgeable of both the possibility of complications and management thereafter. This article details anatomical review, specific procedural technique, and safety considerations to be mindful of when using HA fillers for lip augmentation. J Drugs Dermatol. 2023;21(1):23-29. doi:10.36849/JDD.6304.