Guidry is retiring from the Houston-based independent from 1 September "to spend more time with his wife and family" in the US, the company said on Wednesday.
Chief operating officer Cary Bounds will take over on an interim basis while the company searches for a long-term replacement.
Guidry said: "I believe the ongoing strong leadership provided by the board, Cary and other members of senior management will continue to guide Vaalco forward as the industry emerges from the current downturn."
Chairman
