Abstract The school market was established in Sweden in the conjunction of several reforms, which, among other objectives, aimed at increasing diversity in the market. This allowed profitseeking firms to compete against each other in a former monopoly. According to certain theories, the mechanisms of competition are bound to make organizations more homogenous. Other researchers have claimed that differentiating mechanisms such as various strategies allow companies to become more diverse. This paradox presents an interesting research area which we have pursued. Our thesis addresses this contradiction by answering the research question: How do mechanisms of competition influence organizational diversity among charter school groups? This explanatory qualitative case study analyzes ongoing organizational trends among three Swedish charter school groups through a within – and cross case analysis. Our main findings indicate that 1) the mechanisms of competition reduces the diversity among organizations of charter school groups and thus the organizations are becoming more homogenous. However, 2) external imitation does not contribute to the homogenizing effects on organizations since brand strategy, lack of resources and transparency as well as employee resistance limits competitive imitation.