Mr Byers is set to take on a senior role in public policy and government affairs at BHP Billiton.
A statement released by APPEA Chairman Bruce Lake said that Mr Byers had made a valuable contribution to APPEA and he has been an extremely effective advocate for the industry since joining in 2011.
“The APPEA Board thanks David for his dedication and the Association is committed to continuing the excellent work underway to deliver the safe and environmentally-responsible development of the nation’s oil and gas resources,” said Mr Lake.
The APPEA Board has begun the recruitment process for a new Chief Executive.