Thermophysical properties are important to design the fuel system components and to evaluate new alternative fuels in diesel engine tests. Also, experimental properties allow us to understand the type of interactions present in the studied mixtures. Densities, viscosities, and refractive indices of biodiesel + ethyl levulinate, + ethyl acetoacetate, and + ethyl pyruvate with MgO mixtures have been measured from 288.15 to 338.15 K at 0.1 MPa over the whole composition range and at a constant concentration of 5 × 10 −6 in mass fraction for MgO. Our experimental properties for the pure ketoesters agree with data reported in the literature within an average absolute percentage deviation of 0.056, 3.140, and 0.027 % for density, viscosity, and refractive index, respectively. Vibrating tube densimeter, glass capillary viscosimeter, and Abbemat refractometer have been used to measure the properties. Densities and viscosities of the biodiesel mixtures have been compared with the biodiesel fuel standard EN 14214. Flash point, cetane index, and calorific value of the biodiesel mixtures that meet the EN 14214 norm have been measured. Excess molar volume, viscosity deviation, and refractive index deviation are obtained from experimental data and correlated using the Redlich−Kister equation. Equations reported in the literature are used to correlate the thermophysical properties of the investigated mixtures.