The aim of this study is to introduce the jMetric program which is one of the open source programs that can be used in the context of Item Response Theory and Classical Test Theory. In this context, the interface of the program, importing data to the program, a sample analysis, installing the jmetrik and support for the program are discussed. In sample analysis, the answers given by a total of 500 students from state and private schools, to a 10-item math test were analyzed to see whether they shows differentiating item functioning according to the type of school they attend. As a result of the analysis, it was found that two items were showing medium-level Differential Item Functioning (DIF). As a result of the study, it was found that the jMetric program, which is capable of performing Item Response Theory (IRT) analysis for two-category and multi-category items, is open to innovations, especially because it is open-source, and that researchers can easily add the suggested codes to the program and thus the program can be improved. In addition, an advantage of the program is producing visual results related to the analysis through the item characteristic curves.