Mathematical modeling is considered a bridge to STEM education and has been incorporated into K–12 mathematics curriculums in various countries. However, it has a relatively short history in Hong Kong schools. The lack of high-quality, relevant exemplars of mathematical modeling activities is a challenge to teacher practice in this area. Hence, this study aims to establish a design framework for mathematical modeling activities suitable for teachers and students in Hong Kong. We explore the design and content of the official mathematical modeling exemplars published by the Hong Kong Education Bureau using a document analysis approach. The findings provide the basis for developing a framework to be used in the future design of mathematical modeling activities. Four exemplars were found and analyzed in terms of their structural components, level of learning experience in mathematical modeling, and design characteristics. Based on our findings, we discussed various strategies to enhance the design of a mathematical modeling activity, including setting diversified learning objectives, cross-subject collaboration when formulating the problem context and instructions, designing more activities suitable for average and underperforming students, emphasizing the evaluation of modeling outcomes, and providing relevant supporting materials. Our study thus lays the groundwork for advancing the teaching and learning of mathematical modeling in school contexts. Copyright © 2022 by the authors.