Young children possess the fundamental deductive reasoning skills for solving their upcoming problems in their daily lives. These skills are of great importance for their school readiness and academic development. Therefore, this study aimed to explore the age differences and predictive variables of deductive reasoning skills in young Hungarian children aged 4–8 years old who reside in Hungary and Slovakia. Face-to-face data were collected from 3050 participants. The instrument of deductive reasoning skills assessment was extracted from the school readiness test, DIFER (Diagnostic System for Assessing Development). Utilizing various statistical analyses with R, AMOS, and MPlus8 packages, it was found that there were significant differences in young children’s deductive reasoning skills across countries and age groups. Parents’ education levels had significant positive relationships with children’s deductive reasoning skills development. And the variables of country and age were identified as significant predictors of children’s deductive reasoning skills. And children’s family background variables such as parental education played a significant role in predicting children’s deductive reasoning skills in Hungary. The implications of this study emphasize the importance of educational contexts, parental involvement, cross-cultural exchange, and further research, with the potential to enhance young children’s educational experiences and prospects in Hungary, Slovakia, and beyond.