The construction industry is a major contributor to resource depletion, environmental degradation, waste production, and greenhouse emissions, which makes it necessary to adopt alternative development models. The Circular Economy (CE) has become one of the potential strategies of resource conservation, waste reduction, and environmental equilibrium restoration. This paper aims to provide a systematic literature review of the CE principles by analyzing research papers and articles in scientific journals and some university theses, encompassing the R-Principles (Reduce, Recycle, Reuse, Refuse, Rethink, Repair, Repurpose, Remanufacture, And Recovery), together with principles related to design and production, use and consumption, management and policies, as well as innovation and technology principles. Moreover, examines barriers to the implementation of CE and indicators of assessment. The results show that the adoption of CE in the construction industry is multidimensional and comprises eight broad categories, namely: Political, Economic and Market, Social and Cultural, Technical, Technological, Informational, Administrative, and Environmental Barriers. In addition, the review highlights fragmentation and inconsistency in existing circularity indicators across economic, environmental, and social dimensions. Collectively, the analyzed literature indicates that even though a variety of principles of a Circular Economy can be found, there is still a limited implementation due to the ongoing structural barriers and disjointed approaches to evaluation. The literature review identifies a recurring discrepancy between the theory of the Circular Economy and its practical implementation in the construction industry.