In this study, social competence and school adjustment of the elementary school children that received pre-school education using Montessori Method in early childhood was analyzed. The working group of the study consists of 28 children receiving education in the elementary school in academic year 2011-2012. The experimental group of the study consists of 14 students studying at the first grade and second grade who received Montessori Method pre-school education during early childhood, while the control group includes 14 students that received pre-school education through The Pre-School Education Program of Ministry of Education. The groups were equalized by gender, socio-economic level of the children’s parents and elementary school grade while composing the groups. With an adaptation study to Turkish by Uz Bas (2003), Elementary Education Version of Walker – McConnell Social Competence and School Adjustment Scale was used in this study in order to determine social competence and school adjustment of the working group. In addition, children's demographic information was collected by using a personal information form. Gained data was analyzed by using SPSS 16.0 data analysis program for the social sciences and Mann-Whitney U test procedures were used in the analysis of data. General result achieved in line with the obtained results it that Montessori Method provides a positive contribution to children's social competence and school adjustment and it is more effective in comparison with the pre-school education program in use.