his study demonstrates the possibility of one step printing and multifunctional finishing of wool fabrics using synthesized selenium nanoparticles (Se-NPs) as stable functional colorant. Se-NPs formation was emphasized using visible changes, UV-visible absorption spectra, and transmission electron microscopy (TEM) analysis. The UV-visible spectra and TEM analysis confirmed the synthesis of spherical well-dispersed Se-NPs. The examination of printed samples was conducted by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray powder diffraction analysis (XRD), that revealed the successful deposition of Se-NPs onto wool fabric surface. The color, UV protection, and antimicrobial properties of Se-NPs printed wool were also evaluated. The printed samples had outstanding fastness characteristics to washing, rubbing, and light. Moreover, Se-NPs printed samples were found to possess outstanding antimicrobial activities, excellent UV-protection properties with a remarkable durability after 10 washing times without any negative impact on the printing and softness characteristics.