Major Frank Bernard Halford CBE FRAeS (7 March 1894 – 16 April 1955) was an English aircraft engine designer.

Recalled to engineering duties he improved and enlarged the water-cooled six-cylinder Austro-Daimler, producing the 230 hp (170 kW) Beardmore Halford Pullinger (BHP).

Based on aero-engine principles, it featured an in-line unit construction four cylinder engine, with shaft drive to the rear wheel.

From 1926 he designed the de Havilland Gipsy air-cooled inline engines, repeating the success of the Cirrus.

From 1928 Halford worked with D. Napier & Son, eventually producing the Sabre, an H engine, which became one of the most powerful piston aero engines built, producing 3,500 hp (2.6 MW) from only 2200 cubic inches (36 L) in late-war versions.