The 70-year-old will retire from the board after spending the past 45 years as chairman or chief executive of the group.
He will tell staff: "This is a good time for me to retire from Wood Group. I was 70 in July and had promised my family for some time I would cut back. I want to spend more time on the Wood Family Trust's philanthropic activities, my sons' businesses are growing well and there's also other fairly significant family business interests and investments to look after.
"But, more importantly, it's a good time to step down business-wise. Wood Group is in excellent shape with the PSN acquisition successfully assimilated and all three business divisions performing well."
He will be succeeded by CEO Allister Langlands. Bob Keiller will become chief executive.