In this paper, we report the structural, optical and magnetic properties of nano crystalline samples of Zn1−x(TM)xO (TM = Ni, Co and x = 0, 0.05, 0.10 and 0.15) synthesized by co-precipitation method. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), photoluminescence (PL), micro-Raman, and vibrating sample magnetometer (VSM). It is observed from XRD patterns that all the samples reveal polycrystalline hexagonal wurtzite structure without any extra phase and average particle size decreased with increasing transition metal (TM) doping concentration. FTIR spectrum has been used to confirm the functional group of Ni–O and Co–O bond. SEM images demonstrated the grain like morphologies of TM doped ZnO nanoparticles (NPs). PL spectra of all samples exhibited a broad emission in the visible range. The carriers (donors) bounded on the TM sites were observed from the micro Raman spectroscopic studies. TM doped ZnO NPs showed significant changes in the M–H loop where the diamagnetic behavior of ZnO changes to ferromagnetic nature when doping with Ni and Co ions.