Due to patient compliance and ease, oral drug delivery is the most often used therapeutic administration technique. However, low permeability, enzymatic breakdown, and poor water solubility limit the bioavailability of many medications. Lipid solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), two types of nanoparticles (LNPs), have become potential delivery systems. for enhancing oral drug absorption. This review highlights the classification, functional mechanisms, and formulation factors affecting LNP-based drug delivery systems. This review discusses recent strategies, such as lymphatic transport enhancement, permeability modulation, and drug encapsulation methods. The applications of LNPs in delivering anticancer, antidiabetic, antiviral, and nutraceutical agents are also addressed. Despite regulatory and technical hurdles, continued research and innovation in lipid-based systems have the potential to revolutionize oral drug delivery.