He will be replaced by Laurent Pillet, currently chief executive officer of Pernod Ricard Sub-Saharan Africa.
O’Flynn took on the role in 2011 and became chairman of the Wine & Spirit Trade Association in 2014.
He said: “I have thoroughly enjoyed the last five years at Pernod Ricard UK.
“Working with a great team, I am proud of our continued progress in both the on- and off-trade and our increased market share as well as the consolidation of our company strategy Shaping the Nation’s Drinking Experiences.
“I am also honoured to have been the chairman of the Wine & Spirit Trade Association and to get to know so many people through the last few important years for the UK drinks industry.
“My decision to leave is the right one for me and my family and I am delighted to be returning to Dublin to be with them.
“I leave a great team at Pernod Ricard UK who will take the business to the next level”.