SUMMARY
This study aims at discussing the contributions of Content–based Instruction (CBI) to young learners’ language development in English. Among the three models of CBI, theme-based model has been used in the study, since sheltered and adjunct models are not so functional as theme-based model in Turkish public schools. Experiments have been conducted in both control and pilot groups. The pilot group students have been taught basic language skills in English through theme-based CBI. Both groups have been given an achievement test at the end of the study. The findings indicate that there is a statistically significant difference between the mean scores of both groups in terms of the language development of the young learners. Pilot group can be said to have developed their language skills in English better than those of the control group. Theme-based CBI can be more effective for young learners who are in the process of first language acquisition.