The purpose of the current study is to develop nanostructured lipid carriers (NLCs) for the delivery of the antihyperlipidemic drug simvastatin (SIM) to increase its extremely low oral bioavailability (<5%) and prolong its antihyperlipidemic effect. NLCs were prepared via emulsification-solvent evaporation technique followed by ultrasonication, and the effect of composition of the nanocarriers on the particle size, size distribution, surface charge, entrapment efficiency, drug release kinetics and physical stability was extensively studied. NLCs exhibited nanosized (<200 nm) spherical morphologies with narrow size distribution and high drug entrapment efficiency (>75%), sustained drug release pattern, and negative surface charge (zeta potential of −35–40 mV) that imparts sufficient electrostatic physical stability. When tested in vivo, SIM-NLCs of the optimal composition demonstrated improved and prolonged reduction in the total cholesterol and non-high density lipoprotein cholesterol levels, as compared to the drug suspension. After oral administration of a single dose of SIM-NLC, 4-fold increase in bioavailability was observed, as compared to the SIM suspension. Hence, NLCs might provide efficient nanodevices for the management of hyperlipidemia and promising drug delivery systems to enhance SIM oral bioavailability.