This research was conducted in order to examine the effects of Mother Training Program on language development of 5-6 year old children who cannot benefit from the opportunity of preschool education, in Preparation for Primary Education. The research is based on a trial model. The results of the study showed that Mother Training Program in Preparation for Primary Education achievement average scores of experimental group are higher than the scores of control group. It is also observed that when the language skill levels of children in the experimental group are compared with the ones in control group, the increase in the experimental group is higher.