It is revealed that problem-solving strategies which play a key role in terms of problem-solving process are not subjected to a classification. Through this research study, it is aimed to classify problem solving strategies that are included mostly in the literature based on mathematical process skills. The qualitative dimension of the study was carried out with the data obtained from 21 students studying in the eighth grade of a secondary school in Çanakkale City Center. The data collected by using the "Problem Solving Test (PST)" consisting of eighteen extraordinary problems for the nine most problem-solving strategies in the literature were analyzed by the content analysis method by three field experts and the problem-solving strategies were classified according to mathematical process skills. As a result of the study, it was found that the strategies called "Look for a Pattern", "Draw a diagram" and "Use a Variable" involve both formulation and execution processes; the strategies of "Make a Systematic List" and "Make a Table" involve only the execution process; the strategies of "Working Backwards", "Guess and Check" and "Logical Reasoning" involve both execution and interpretation, evaluation processes and the strategy of "Simplify the Problem" involves the processes of formulation, execution and interpretation, evaluation.