Background: Due to the variations in tooth anatomy and size among different populations, this study aimed to compare the mesiodistal width of primary second molars in Iraqi children with the mesiodistal width of stainless-steel crowns from different companies. Materials and Methods: This cross-sectional study was conducted on 220 intact maxillary and mandibular primary second molars selected from boys and girls’ Iraqi children aged 8-9 years collected from different primary schools in Baghdad city. The mesiodistal dimensions of the selected teeth and the available maxillary and mandibular stainless-steel crowns from three different companies were measured by using a 3-D scanner, and then the whole measurements were calculated using 3 shape Ortho-analyzer software program. Results: Data were analyzed statistically via SPSS V 26 software and the results showed that there’s non-significant difference between the MD measurements of second primary molars between right and left sides, and high significant difference were recorded with higher mean values for boys than girls. When comparing the same mesiodistal measurement between molars with that of stainless-steel crowns, only limited sizes of stainless steel crowns were found to be fitted to the molars of Iraqi children. Conclusion: more studies need to be applied using other stainless steel crown companies to find the relation in the mesiodistal measurement of Iraqi populations.