The 800 series has a number of modifications and changes over the 700; most noticeable was the redesigned cockpit windscreen. Accompanying this are a modified rear fuselage fairing as well as a glass cockpit and updated (from 3,700 to 4,300 lb) Garrett TFE731-5R-1H engines. British Aerospace also improved the wing by incorporating new outer wing sections. This helped to reduce drag and improve aerodynamic efficiency.

The twin-engine British Aerospace BAe 125 is the world's best selling mid-size corporate jet, with newer variants now marketed as the Hawker 800. The aircraft went through many designation changes during its service life. Originally DH.125, it was renamed the HS.125 after de Havilland became a division of Hawker Siddeley in 1963. When Hawker Siddeley Aircraft merged with the British Aircraft Corporation to form British Aerospace in 1977, the name changed to BAe 125. Then, when British Aerospace sold its Business Jets Division to Raytheon in 1993, the jet acquired the name Raytheon Hawker. The fuselage, wings and tail-fin are to this day fully assembled and partially equipped (primary and secondary flight controls) in Airbus UK's Broughton plant in Wales.