Lloyd, who joined Which? in 2011, has been involved in a series of investigations, including The Competition and Market Authority (CMA) probe into energy market.
He said: “I am immensely proud of how many more people Which? is now helping in their daily lives, and how effectively we take the views of consumers to business leaders, ministers, regulators and the media.
“I have been privileged to lead all this work and I will miss the daily contact with people running some of our biggest institutions and businesses. But most of all I will miss my extraordinary, talented teams, absolutely committed to making positive change happen.
“I hope that in the future I will have the opportunity to serve other groups that matter as much as Which?.”
Which? group chief executive Peter Vicary-Smith said: “Richard has been absolutely central to the success and prominence of Which? for half a decade.
“He can be rightly proud of the organisation he has done so much to develop, and we wish him well in whatever he decides to do next.”
Richard will leave Which? on 20 May and take a break over the summer before pursuing a new role.