The study compared the effects of Learning Objects (LOs) within different applications; in classroom and in extracurricular activities. So in this study, firstly a Learning Object Repository (LOR) has been designed in parallel with 9th grade school mathematics curriculum. One of the two treatment groups was named as "classroom group" (n = 24) used LOs with the guidance of the teacher during lessons in a computer lab, another group named as "project group" (n = 26) used LOs at home with the aim of preparing projects and assignments. Students in both groups used LOs during 11 weeks. A pre-test and post-test quasi-experimental design was used. Test results are compared in different learning domains (sets, numbers, relations and functions). In addition the interviews with the teacher and the observations inside the class were taken into account for revealing the reasons about the change on academic achievements. The results of the study about students' academic achievements showed that; LOs use in classroom activities were more effective than LOs use in extracurricular activities if sets, numbers, relations, functions and operations domains are considered together. Nevertheless this study supported the idea of "LOs can be used in both in classroom activities and in extracurricular activities". (Contains 1 figure and 9 tables.)