In recent years, studies have been done to examine whether geometry education programs prepared for preschool children are effective in improving geometry skills of children. Research results show that geometry skills of children can be developed at an early age with educational programs (Casey, Erkut, Ceder, & Young, 2008; Fisher, Hirsh-Pasek, Newcombe & Golinkoff, 2013; Gecü Parmaksız, 2017; Kalenine, Pinet & Gentaz, 2011; Keren & Fridin, 2014; Kesicioğlu, 2011; Şen, 2017; Zaranis, 2012). Studies done are relatively limited. Within this context, the aim of the study is to examine the effect of Preschool Geometry Education Program (Okul Öncesi Geometri Eğitim Programı- OGEP) prepared for preschool children, on geometry skills and figural creativity of children. The research was carried out using quasi-experimental design from quantitative research method with a pretest-posttest control group. The study group of the study consisted of 34 children that are 5-6 years old receiving preschool education. The study group was determined by criterion sampling which is one of the purposeful sampling methods. Children are between the ages of 5 and 6 and are enrolled in an official pre-school education institution, being socio-economically disadvantaged and have not participated in any geometry or mathematics education program before. The experimental and control groups was determined randomly. Accordingly, 17 children in the morning group were included in the control group and 17 children in the lunch group were included in the experimental group. Thus, it was ensured that the children participating in the study were not affected by each other. The demographic data of the children in the study group were collected using the "Personal Information Form", Early Geometry Skill Test (EGBT) developed by Sezer (2015) and the Torrance Creative Thinking Test Figural Subtest originally developed by Torrance (1984) and adapted to Turkish by Aslan (2001). For the pre-tests of the experimental study, Early Geometry Skill Test (EGBT) and Torrance Creative Thinking Test (TTCT) Figural Subtest A Form were simultaneously applied to the children in the experimental and control groups. After pretests were completed, the children in the experimental group participated in the activities of OGEP for 10 weeks as 3 days a week. The children in the control group during this process and these children continued their education according to the Ministry of Education (2013) Preschool Education Program. After the applications of OGEP were completed, posttests were carried out by applying EGBT and TTCT Figural Subtest B Form to the children in the study group. In order to test whether the effect of OGEP is permanent or not, the retention test was performed by applying EGBT and TTCT Figural Subtest A Form to the children in the experimental group 4 weeks after the posttests. The data were analyzed using the SPSS 21.0 package program. Descriptive statistics (percentage, frequency, mean and standard deviation) and difference tests (Mann Whitney U test, Wilcoxon Signed Ranks test) were used to analyze the data. According to the findings, it was concluded that the Preschool Geometry Education Program prepared for preschool children is effective in improving geometry skills of children and this effect is permanent. Similar to the results of this study, it is seen that the education programs applied in the studies on geometry in the preschool period are effective in developing the knowledge and skills of children about geometry (Aydoğan Akuysal, 2007; Casey, Erkut, Ceder & Young, 2008; Çiçek, Aytekin, Duysak & İnan, 2012; Keren & Fridin, 2014; Sancak, 2003; Zaranis, 2012). It is emphasized that educational programs focused on mathematics are effective in developing mathematical skills of children. In specialized mathematics education programs, children can develop deeper mathematical ideas and skills by participating more intensively in mathematics activities (Çelik & Kandır, 2013; Hofer, Farran & Cummings, 2013; Presser, Clements, Ginsburg & Ertle, 2015). In this study, it is thought that the children in the experimental group participated in geometry activities more intensively and systematically, was effective in improving their geometry skills due to their participation in a special education program focused on geometry education compared to the control group.