In this work, the dielectric and magnetic properties of (Co, Ni) co-doped SnO2 nanoparticles were studied using ac impedance spectroscopy and magnetic properties measurement system or quantum design superconducting quantum interference device. Results showed that dielectric constant (er), dielectric loss (e″), and ac electrical conductivity (σAC) are strongly frequency dependent. A decrease in frequency was accompanied with an increase in er and e″ values, whereas, a decrease in the dielectric constant was observed with the increase of Ni co-doping concentration. It was found that the dielectric constant and dielectric loss values decrease, whilst AC electrical conductivity increases with increase in co-doping concentration. Magnetization measurements revealed that the Ni co-doped SnO2 samples exhibits room temperature ferromagnetism. The results illustrate that (Co, Ni) co-doped SnO2 nanoparticles have an excellent dielectric, magnetic properties, and high electrical conductivity than those of co-doped samples reported previously, indicating that these (Co, Ni) co-doped SnO2 materials can be suitable for the purpose of high frequency device and spintronic applications.