This thesis explores the fundamental and applied aspects of quantum entanglement in the context of next-generation communication systems. Quantum entanglement, a nonlocal correlation between quantum systems, offers revolutionary capabilities for secure communication, quantum key distribution (QKD), and teleportation protocols. The work presents the theoretical foundation of entangled states, Bell inequalities, and teleportation, while analyzing QKD protocols such as BB84 and E91. Recent experimental advancements—including long-distance satellite-based QKD—are reviewed to highlight real-world implementations. The role of entanglement in quantum sensing, metrology, and distributed quantum computing is also discussed. Mathematical formulations and graphical simulations are included to illustrate the impact of noise and environmental decoherence on fidelity. The thesis concludes with a discussion on current technological limitations, ongoing global initiatives for a quantum internet, and the future outlook for scalable entangled networks. This research aims to contribute to the growing body of work bridging quantum theory and practical communication technologies.