Honeycomb core laminates have become a key component in aerospace engineering, especially in wing design and construction, thanks to their outstanding strength-to-weight ratio, energy absorption, and structural efficiency. This chapter offers an overview of honeycomb structures, starting with their historical development in aerospace applications. It discusses the fundamentals behind honeycomb geometry and mechanical behavior under quasi-static and dynamic loads. The chapter also gives the manufacturing techniques used for honeycomb cores and sandwich structures. Testing methodologies, including static and dynamic tests, and failure modes, are covered to ensure structural integrity and long-term reliability.