The exponential growth of global telecommunication networks has heightened the need for robust security frameworks to protect data transmission against evolving cyber threats. Traditional encryption techniques, such as RSA and AES, while effective, are increasingly vulnerable to advances in computational power and the impending threat posed by quantum computing. Quantum cryptography, specifically Quantum Key Distribution (QKD), presents a revolutionary approach to securing telecommunication systems by leveraging the fundamental principles of quantum mechanics. Unlike classical encryption methods, QKD guarantees data security through the use of quantum states that are inherently resistant to interception and eavesdropping due to the no-cloning theorem and Heisenberg's uncertainty principle. From a broader perspective, this paper explores the integration of quantum cryptographic protocols into existing telecommunication infrastructures, emphasizing their potential to safeguard data transmission in fiber-optic and satellite communication networks. It examines the architecture and operational mechanisms of QKD systems, detailing protocols such as BB84 and E91, and evaluates their effectiveness in countering both classical and quantum-enabled cyber-attacks. Additionally, the study delves into the challenges of large-scale deployment, including key distribution range limitations, hardware requirements, and the need for quantum repeaters to support long-distance secure communication. Narrowing the focus, case studies on the implementation of quantum cryptography in 5G networks and global telecommunication hubs are analysed, highlighting their role in enhancing network resilience and ensuring end-to-end encryption. The paper concludes with strategic recommendations for policy development, international standardization, and future research directions to facilitate the widespread adoption of quantum cryptography in the telecommunications sector.