In this study, the effects of different organic additives on the formation of europium-doped yttrium orthovanadate (YVO4:Eu3+) microspheres under hydrothermal conditions were investigated. The organic additives employed were sodium dodecyl sulfate (SDS) as an ionic surfactant, polyvinylpyrrolidone (PVP) and ethylene glycol (EG) as nonionic surfactants, disodium ethylenediaminetetraacetic acid (Na2EDTA) as an organic salt, and acetone as an organic solvent. The as-synthesized samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy. The experimental results demonstrated that the organic additives in the hydrothermal system played an important role in the formation of YVO4:Eu3+ powders with different morphologies and sizes, as follows: ellipsoids (SDS) → irregular microspheres (acetone) → inhomogeneous microspheres (EG) → uniform microspheres with the diameter of 4–5 μm (PVP) → uniform microspheres with the diameter of 1–3 μm (Na2EDTA). The luminescence properties were greatly affected by the morphologies and sizes of the as-synthesized samples. The highest emission intensity was observed in the sample hydrothermally synthesized with Na2EDTA due to the formation of uniform microspheres with less aggregation.Graphical abstract