Derek Hallas (born c. 1934) is an English former rugby union and professional rugby league footballer who played in the 1950s and 1960s, and coached rugby league in the 1960s. He played representative level rugby union (RU) for Yorkshire, and at club level for Roundhay RFC, as a centre, i.e. number 12 or 13, and representative level rugby league (RL) for Great Britain and Yorkshire, and at club level for Keighley (two spells), Leeds (Heritage №), Parramatta Eels (Heritage № 220) and the Inverell Hawks (captain), as a centre, i.e. number 3 or 4, and coached at club level for the Inverell Hawks.