The usage of three dimensional (3D) virtual worlds in Mathematics Education not only eliminates the dependence of education on K-12 schools but also enables the subjects to be more concrete. The objective of this study is to create a mathematics laboratory by using the virtual classroom qualities of 3D worlds. In this lab, abstract mathematics subjects are concretised by the materials developed. This state makes the learning of secondary school students, who still think concretely, easier and more consistent. In our country, Turkey, studies on three dimensional virtual worlds exist in Management, Sociology, Fine Arts, Architecture, Science and Technology. In terms of teaching, there are only studies in the field of Foreign Language. No studies are available about its contribution in Mathematics Education yet. For the objective of this study, an experiment group of 28 people was chosen from Fatih Secondary School third grade students. The teaching of Mathematics to this group was supported by Second Life. At the beginning and at the end of the study, an achievement test was applied. With this study, the positive effect of three dimensional virtual worlds on Mathematics education was observed together with the change of student success in Mathematics courses, and it was found significant at a level of 0.01.