A facile synthetic strategy was implemented to obtain nanosized barium titanate (BaTiO3) powders with tetragonal structure. The nanoparticles were synthesized using solvothermal process employing diethanolamine and triethanolamine to suppress the particle growth and the as-prepared nanopowders were characterized using X-ray diffraction, scanning electron microscopy, and high-resolution dispersive Raman spectroscopy. It was found that the particle size can be easily tuned by adjusting the experimental parameters while retaining the tetragonality. The average diameters of the particles prepared with and without the organic amines were found to be 80 and 100 similar to nm, respectively. All the synthesized BaTiO3 nanopowders exhibit a narrow size distribution with a uniform morphology. Rietveld refinement of the XRD patterns and Raman spectra revealed that the synthesized BaTiO3 nanopowders have tetragonal asymmetry dominant structures. A slight decrease in the tetragonality of the prepared powders with decrease in particle size is attributed to the presence of cubic shell layer and inner defects. The tetragonal-dominant structure was also confirmed by normalizing the peak area of the Raman spectra.