In developing countries, child labour is an important problem due to the low economic situation. According to the statistics of ILO, there are almost 250 million working children in the world, and almost four million of them are working in Turkey. It is a well known fact that working has detrimental effects on the physical, emotional and cognitive health of children. One of those effects on the emotional development of working children is found to be on their self-concepts. Therefore, this comparative research aimed to examine and compare the self-concept levels of working and non-working children, and whether the socio-economic situation of those children has an effect on their self- concepts. Moreover, some demographic information about working children was gathered and some of them were analyzed in relation with their self-concepts. Results of the study indicated that working had an impact on the self-concept levels of children; on the other hand, socio-economic factors and some selected work-related characteristics did not have an impact on the self-concept levels of children.