This research investigates similarities and differences in young children's early numeracy skills related to age, nationality and gender. The participants were five- to seven-year-old children from Finland and Iran. Early numeracy was investigated by using tasks measuring number-related relational skills (e.g. comparison, one-to-one correspondence) and counting skills (e.g. enumeration, number-word sequence skills). A hybrid multigroup, multiple-indicator-multiple-cause (MIMIC) approach to factorial invariance and latent mean differences between groups was used. The results showed that Finnish children had better scores in relational and counting tasks than did children in Iran. There was a gender difference in relational skills favouring girls in both countries. Younger children had weaker early numeracy skills than the older children in both countries. Comparing age groups in both countries shows a bigger difference in counting skills between young Iranian and Finnish children than between older children in both countries. The results are discussed in the context of early mathematics learning and gender equity in schooling. (author abstract)