We report on the synthesis of ultrathin SmVO₄ nanosheets through a simple and facile ionic liquid-assisted hydrothermal approach and their application in luminescence properties. The as-prepared products were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy/high-resolution TEM, energy dispersive X-ray microanalysis, Fourier transform infrared spectrometry and photoluminescence technique. The SmVO₄ nanosheets had a tetragonal (t-) structure with the thickness of 10–20 nm and the size in the range of 10–12 μm. We found that the amount of ionic liquid, pH value and synthesizing temperature played crucial roles in controlling the structure and morphology of as-prepared samples. Particularly, the amount of ionic liquid [BMIM]Br can effectively control the shape of t-SmVO₄ nanostructures by adsorption on the (001) plane of the crystals, resulting in their preferential growth along the [100] and [010] directions via hydrogen bond-co-π–π stack interaction. A dissolution-recrystallization process was reasonably proposed to understand the formation mechanism of t-SmVO₄ nanosheets based on the experimental results. In addition, the photoluminescence spectra reveals that the as-prepared t-SmVO₄ nanosheets exit red emission related to ⁴G_5/2→⁶H_7/2 transition.