Cobalt molybdate (CoMoO4) and its rare earth doped variants have emerged as promising photocatalysts for degrading dye pollutants in wastewater. The photocatalysts were prepared using a modified sol-gel method, employing ammonium heptamolybdate tetrahydrate and cobalt (II) nitrate hexahydrate as precursors. The incorporation of samarium and erbium as a dopant was hypothesized to improve the photocatalytic activity of CoMoO4 by altering its band structure and creating defect sites for improved dye adsorption and degradation. The structural and optical properties of the synthesized photocatalysts were characterized using various techniques. The photocatalytic performance of CoMoO4, Sm:CoMoO4 and Er:CoMoO4 was evaluated by monitoring the degradation of MB dye under light irradiation. The results reveal that Sm:CoMoO4 and Er:CoMoO4 catalysts achieve a degradation efficiencies of 99 % and 97 %, respectively, highlighting the potential of rare earth-doped CoMoO4 as an efficient photocatalyst for the remediation of dye contaminated wastewater.