Necatibey Eğitim Fakültesi Elektronik Fen ve Matematik Eğitimi Dergisi (EFMED) Cilt 13, Sayı 2, Aralık 2019, sayfa 1305-1337. ISSN: 1307-6086 Necatibey Faculty of Education Electronic Journal of Science and Mathematics Education Vol. 13, Issue 2, December 2019, pp. 1305-1337. ISSN: 1307-6086 Araştırma Makalesi / Research Article The Effects of Differentiated Geometry Teaching for Gifted Students on Creative Thinking, Spatial Ability Level and Achievement Gülşah BATDAL KARADUMAN 1 , Ümit DAVASLIGİL 2 1 İstanbul University-Cerrahpaşa, Hasan Ali Yücel Faculty of Education, gulsah@istanbul.edu.tr, 2 Maltepe University, Faculty of Education, umitdavasligil@maltepe.edu.tr, Received : 03.12.2019 Accepted : 1.1.2020 Doi: 10.17522/balikesirnef.654451 Abstract – This study deals with developing, applying, and testing effectiveness of a geometry program in order to meet the needs of the gifted students, who has different cognitive features. The study was conducted with a total number of 32 students, 16 of them in study group and 16 in wait list control group, who were students from 5th grades. Creativity test which is developed by K. Urban and H. G. Jellen, Spatial Test Battery and a Geometry Achievement Test which is developed by the researcher are used in order to derive the needed data. All three scales are applied as pre-test and post test. Statistical analyses were conducted via Mann Whitney-U test and Wilcoxon signed-ranks test techniques. The results of the study revealed that the special problem based program which was developed for the gifted students, increases the achievement, spatial ability and creative thinking level of the students. Key words: Geometry teaching, gifted individual, creativity, visual-spatial talent, parallel curriculum. ------------ Corresponding author: Gülşah BATDAL KARADUMAN, İstanbul University-Cerrahpaşa, Hasan Ali Yücel Faculty of Education. Summary Summary Purpose Although gifted and talented students seem to be luckier when compared to the other students, they can find themselves in less advantageous situations if they are not provided with educational opportunities which are special for them. A study to develop a geometry teaching program which is for gifted and talented students, suitable for their specific needs and aims to develop their creative thinking and spatial abilities forms the main problem of this study.