Paramagnetic magneto-optical glasses doped with different rare-earth ions, 32GeO2–15B2O3–5P2O5–3ZnO-45Tb2O3-RE (RE = 0, 1Ho, 1Pr, 1Er, 1Nd, 1Dy, or 1Ce), referred to as GBPZ-T45-RE magneto-optical glasses, were prepared using a high-temperature melting technique. The effects of rare-earth ion doping on the structure, physical parameters, and magneto-optical properties of these GBPZ-T45-RE glasses and the effects of incident-light wavelength and temperature on the values of the Verdet constants were researched. The refractive indexes and theoretical optical basicities of the glasses were obtained by theoretical calculations. Notably, GBPZ-T45-RE glasses exhibited a large Verdet constant and superior magneto-optical performance; especially, Ho3+ and Pr3+ ions were the most effective in improving the magneto-optical properties. In addition, the Verdet constants were affected by temperature. The Verdet constants of GBPZ-T45-Ho and GBPZ-T45-Pr were determined to be −172.44 and −175.22 rad/(T·m), respectively, under 633 nm light at 298.15 K, values that are significantly greater than that the commercial terbium gallium garnet TGG crystal (−134 rad/(T·m)). The Verdet constants of GBPZ-T45-Ho and GBPZ-T45-Pr under 633 nm light increased to −254.93 and −255.92 rad/(T·m), respectively, at 273.15 K. The excellent magneto-optical properties of these glasses should enable their widespread application in optics, electricity, magnetism, information, communications, military operations, aviation, satellite measurement and control systems, and other fields.