In an increasingly complex world, the development of logical reasoning skills is vital for students of all ages. This study investigates the impact of the Logical Intelligence Enhancement Program (LIEP) on the logical reasoning skills of a large sample of primary school students aged between eight and eleven. The research encompasses 54 classes across nine Italian state primary schools, with half of the classes participating in the LIEP training and the other half forming the control group. Results demonstrate significant improvements in logical reasoning abilities among the students who participated in the LIEP training, as indicated by both near and far effects on tasks assessing logical reasoning (an LIEP-like task for near effect and the Matrix Reasoning subtest of the WISC-IV for far effect). Student and teacher feedback reinforces the programme's positive influence on cognitive development and learning experiences. These findings underscore the potential value of LIEP for strengthening critical thinking skills in primary education.