The societal shift towards the circular economy is gaining momentum due to the push from the legislation side and the increasing social awareness towards the ecological imbalance caused by the linear model of resource extraction and consumption. The topic of design for the circular economy is gaining increasing interest in both academia and industry. The circular economy requires products to be designed based on a lifecycle approach and extended lifetime.This thesis aimed to investigate the potential application of modular design strategy as a supportive approach to aid Original Equipment Manufacturers (OEMs) in their bid to adapt their product features to fit within a circular economic model. Furthermore, the study has investigated the potential challenges encountered during the adoption of such a design strategy and concludes with recommendations to overcome the identified challenges.To address this aim, a case study was carried out within a global OEM, based on their interest in exploring the circular economy's design domain. A literature review and interviews have been conducted to assess how product circularity factors can be addressed using a modular design strategy and identifying the potential challenges that can hinder its realization.The study initially identified seven design factors that need to be addressed along the different phases of a product lifecycle to ensure a fit within a circular economic model. The seven circularity factors are design: based on a lifecycle approach, for durability, for adaptability, for upgradability, for ease of maintenance and repair, for ease of disassembly and reassembly, and standardization and compatibility.The study also revealed that a standardized and simplified interface between different modules within the product plays a vital role in enhancing its ability to address the different circularity factors. The standardized interface in the modular product qualifies the product to become useable for multiple usage cycles. Furthermore, such a modular product can be considered an open-source product since it can continuously be updated with the latest available technology. Such continuous updates allow the open-source product to adapt to the changes in the working environment effectively.Despite the capability of a modular design strategy to address the different circularity factors, several challenges can hinder its implementation in the industry. The primary challenge industries face when adopting such a strategy is identifying the main objectives of such an approach. Further, this strategy might negatively impact product profitability, which is a significant challenge for the industries. Moreover, the prospect of adopting modular strategies also faces design challenges, such as the potential of losing customer interest in a modular product.The thesis concludes with a few recommendations to overcome these challenges associated with adopting a modular design strategy for a circular economy. To overcome such challenges, industries need clear identification of the circular economy and the planned outcome of such a manufacturing shift based on clear systems thinking and transparency in product development. In the end, the study proposes a design framework, which may provide industries with a transparent methodology for designing a modular product for a circular economy.