Adlington, who currently holds the world record in the 800 metres freestyle, won two golds in Beijing in 2008 and two bronze medals at London 2012.
"I'm very proud of what I have achieved so far, but my journey is not finished yet," Adlington said on her personal website (www.rebeccaadlington.co.uk).
"My vision is that every child in Britain will be able to swim 25 metres by the time they leave primary school. Being able to swim is such a wonderful life skill, and I see this as my greatest challenge in swimming."
Adlington, who finished third behind 15-year-old American Katie Ledecky in the 800 metres freestyle at the London Games, also won World, European and Commonwealth Games gold medals.
The 18-times Olympic gold medal winner Michael Phelps led the tributes.
"Our paths have crossed many times over the years - at meets and through a shared sponsor," he said.
"Her accomplishments speak for themselves, she has been a great representative for British Swimming and the sport overall. I congratulate her on a fantastic career and wish her all the best in the future."