The aim of this study is to design a function that will easily calculate Grey Relational Grades by calling a function in MATLAB environment. Grey Relational Analysis (GRA) is a member of Grey System and it has successfully applied as a decision support tool in many areas. It is a nonparametric tool and it is possible to make decisions by using relatively small dataset which make it an attractive method. In this study, first the theory of the Grey Relational Analysis is presented and secondly the steps of the GRA function is explained in detail. In addition, a problem, which is solved and published in literature, is solved by using the function presented in the study. Designing a function for Grey Relational Analysis will enable researchers to use it in different areas and for different purposes.