When we talk about sustainability for a city, the first things that come to mind are fundamental concepts such as the smooth and trouble-free delivery of services, and ensuring that these services do not harm the environment, nature, or human health. At the same time, sustainability refers to a developing city’s ability to maintain its physical structure in a healthy and appropriate manner, as well as to protect the health and well-being of its local population. The ability of a city to provide sustainable prosperity is significantly influenced by its capacity to protect the health and well-being of its local population. Smart urbanization, one of the most important concepts supporting today's understanding of sustainability, is poised to become one of the key stages for digital twin applications, which are among the latest products of technology.

The subject of this chapter is to reveal the effects of the applicability of the digital twin application, one of the latest innovations in developing technology, in ensuring security in smart cities, where the number of applications used within the scope of sustainability is increasing day by day and new ones are being added every day. The chapter aims to demonstrate the applicability of digital twin technology in efforts to control security in cities shaped by sustainability principles.

The chapter involved collecting data through a literature review on sustainability, urban security, and digital twin concepts. Recommendations were made highlighting the potential positive contributions of aligning security practices in smart cities that embrace sustainability with digital twin applications. In the chapter, within the scope of qualitative research methods, open-access internet sources such as books, journals, and articles were subjected to document analysis and classified using systematic analysis methods. End of this chapter will reveal how digital twin applications can be made compatible with smart city security applications and to what extent technology can be effective in ensuring security.