The current study used ultrasound-assisted chemical precipitation to create zinc doped beryllium oxide (BeO) nanoparticles. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the synthesized samples. The effect of sonication on the size of zinc-doped BeO nanoparticles is discussed. The presence of zinc-doped BeO nanoparticles with an average crystallite size of 17.89 nm was established by X-ray diffraction. The FTIR peaks at 434.97 cm-1 and 1,110.08 cm-1 confirm Zn and Be in them. Sonication was used to disperse the nanoparticles in ethylene glycol, resulting in a nanofluid. The nanofluids were prepared in six concentrations from 0.0005 to 0.0030 wt% and characterized by ultrasound velocity and Fourier transform infrared (FTIR) spectroscopy as well as photoluminescence. Ultrasonic studies and FTIR analysis confirmed the absence of particle-fluid interactions. The maximum intensity was at 510 nm wavelength in the photoluminescence spectra, giving the electron transition energy. Thermal conductivity and viscosity revealed an optimum concentration at 0.0025 wt% zinc-doped BeO in ethylene glycol nanofluid, for maximal heat transfer with the highest thermal conductivity of 0.265 W/mK.