Wireless communication has continuously shaped how cities grow and function. In recent years, the concept of smart cities has emerged as a way to improve urban living through connected technologies. While 5G has already enhanced connectivity, the upcoming 6G networks are expected to take this transformation much further. With extremely high data speeds, near-instant communication, and intelligent network capabilities, 6G can significantly improve how city systems operate. This paper examines how 6G can support smart city development in areas such as transportation, healthcare, energy management, and public safety. It also highlights key challenges, including security concerns, high deployment costs, and technical limitations, while suggesting possible future research directions.