K-Nearest Neighbors algorithm is one of the most used classifiers in terms of simplicity and performance. Although, when a dataset has many outliers or when it is small or unbalanced, KNN doesn't work well. This paper aims to propose a novel classifier, based on K-Nearest Neighbors which calculates the local means of every class using the Power Muirhead Mean operator to overcome alluded issues. We called our new algorithm Power Muirhead Mean K-Nearest Neighbors (PMM-KNN). Eventually, we used five well-known datasets to assess PMM-KNN performance. The research results demonstrate that the PMM-KNN has outperformed three state-of-the-art classification methods in all experiments.