The current research investigated the effect of a program based on personalized learning in developing primary school pupils' English morphological skills. Participants were 50 fourth year primary school pupils from a public school in Egypt. They were randomly selected and divided into a control group and an experimental group. The research depended on the quasi experimental pre -post design. The groups were pretested and post tested on the EFL morphology test, designed by the researcher, before and after the administration of the suggested program. Statistical analysis of the data obtained from the pupils' test scores revealed that the experimental group outperformed the control one in the post administration of the EFL morphology test. The suggested program based on personalized learning had a large effect size (d=7.0 ), and developed primary school pupils' EFL morphological skills. It was recommended that personalized learning profile, personal learning paths, and flexible learning environments were effective PL strategies in developing English morphological skills.