The rise of quantum computing introduces risks to classical encryption systems, emphasizing the need for more resilient alternatives. Post-quantum cryptography (PQC) offers a practical short- to medium-term solution but still relies on classical cryptographic principles, which may have inherent limitations. Quantum key distribution (QKD), on the other hand, aims to provide a fundamentally higher level of security—information-theoretic security—that classical methods cannot achieve. However, QKD faces several challenges, including scalability and cost, which require further technological progress to address. This chapter critically examines the key challenges associated with QKD and explores the potential for overcoming its current limitations through ongoing research and future advancements.