Iron oxide nanoparticles (IONPs) were green synthesized using an aqueous leaves extract of Christ’s thorn jujube and were characterized by TGA, FTIR, XRD, HRTEM and FESEM. A carbon paste electrode (CPE) modified with the synthesized iron oxide nanoparticles (IONPs–CPE) was fabricated. The new IONPs–CPE sensor was employed to investigate the electrochemical behavior of paracetamol (PA) in the BR buffer solution. The impact of supporting electrolyte, pH and scan rate has been contemplated. High electrocatalytic activity, low detection limit, good selectivity and stability appeared to the modified electrode towards PA determination. The LOD and LOQ of PA were about 0.287 and 0.871 µM with a linear dynamic range of 0.8–10 µM. In addition, the IONPs–CPE has been used to determine PA in commercial tablets samples.