The concentration of potentially toxic elements (PTEs) in samples of mustard greens from sub-sites of the southern districts of Punjab, Rajan Pur (RP), Dera Ghazi Khan (DGK), and Rahim Yar Khan (RYK) was assessed using atomic absorption spectrometry (AAS). The mean concentrations of PTEs in mustard greens samples from sub-sites of district RP were in decreasing order of Fe>Zn>Mn>Cu>Cr>Co>Cd>Pb>Ni. The mean concentrations of PTEs assessed among the mustard green samples from sub-sites of district RYK were determined in the order of Fe>Mn>Zn>Cu>Cr>Co>Cd>Ni>Pb. The mean concentrations of PTEs among mustard greens samples from sub-sites of district DGK have shown the order of Fe>Mn>Zn>Cu>Cr>Cd>Ni>Pb>Co. Mean concentrations of Fe were found to be highest among all the districts (DGK: 11.16 mg/kg, RYK: 9.281 mg/kg, and RP: 5.821 mg/kg) than any other PTE mean concentrations. Concentrations of Mn from all sub-sites of all three districts (RP, DGK, and RYK) and concentrations of Co from Sadiq Abad Sardar Garh, and Feroza were exceeding the allowed maximum residue limits (Mn: 0.2 mg/kg and Co: 0.1 mg/kg) recommended by the Food and Agriculture Organization (FAO) and World Health Organization (WHO). Values of chronic dietary intake (CDI) for Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were recorded under the safe limits suggested by FAO/WHO 0.001, 0.03, 0.003, 0.037, 0.7, 0.083, 0.02, 0.0015, and 0.3 (in mg/kg/day), respectively. The hazard quotient (HQ) and cancer risk (CR) levels for all said PTEs were analyzed under the limits (HQ: <1, CR: 10-6-10-4). Results indicate that the mean HQ values of all the said PTEs found under the threshold limits (<1) are within the safe limits. CR for all mentioned PTEs were under the permissible limit (10-6-10-4), revealing that there is no apparent risk to health. The findings are very useful for the end users and the food safety authorities to consider for the suitable measures to be taken. These findings will thus prompt the relevant parties to take the required precautions against hazardous metal exposure.