This study reports on the evaluation of a "summer pre-school model" as an intervention measure. A 10-week program was designed to increase the school readiness of Turkish children from disadvantaged and multilingual environments by supporting their cognitive and linguistic skills during the summer prior to the start of school. The intervention consisted of a Pre-school Education Program with a special focus on Turkish language, pre-literacy and pre-numeracy skills. The evaluation study was carried out on its first implementation in a southeastern province of Turkey where it was attended by bilingual six-year-olds. A pre-post, control-group, quasi experimental design was used with 92 intervention trained and 93 non-trained control children from the same neighborhoods. Compared to the control children the intervention children scored significantly higher on post-test measures of pre-literacy and pre-numeracy skills, and on measures of syntactic knowledge and story comprehension. The results also revealed the importance of the educational level of the mother for progress in language skills. The findings indicate the overall short-term effectiveness of the program and of the summer pre-school model as a primary prevention strategy that aims to bring children at risk to a higher level of school readiness. (Contains 10 tables.)