Abstract <p>The article presents the results of investigation of the morphology and elemental composition of refractory metals multioxide particles synthesized under conditions of laser ablation of a high-entropy alloy. The alloy was obtained by spark plasma sintering of an equiatomic mixture of powders (W–Ta–Mo–Nb–V–Zr–Cr–Ti) after preliminary high-energy ball milling. It was found that the multioxide particles formed under conditions of laser ablation with sizes from 20 to 80&#xa0;nm have a spherical or quasi-spherical shape and are characterized by an almost uniform volume distribution of oxygen and refractory elements. The results of transmission electron microscopy and X-ray diffraction analysis indicate an amorphous-crystalline structural state of the multioxide particles. After annealing at a temperature of 700&#xa0;°C, the particles, while maintaining nanoscale sizes, acquire a nonequiaxed shape with partial faceting. With the complex use of structural investigation methods, it was found that almost the entire volume of the powder mixture transforms into a crystalline phase characterized by a tetragonal lattice. Low-angle fragmentation boundaries and areas with high crystal lattice curvature were found inside the particles. It is assumed that residual local stresses are a consequence of local imperfection of the crystal lattice (dilations and distortions due to differences in the sizes of atoms), which can be represented as partial disclinations and their configurations.</p> Graphical Abstract <p></p>