The 32-year-old became Wales' first medallist at London 2012 when he won silver in the lightweight men's four after they missed out on gold to South Africa by less than a second.
Bartley, from Wrexham, was part of the men's four at Rio, but the team missed out on the medals, finishing seventh.
In 2010, Bartley won gold with the men's lightweight four at the World Rowing Championships in New Zealand.
"I've had quite a long career. I've been involved in the sport internationally for more than 10 years," he told BBC Radio Wales.
"I've got more than I ever thought that I would out of the sport and I thought it was the right time for me to call it a day."

He is backed by 152 constituency parties, with Andy Burnham in second place with 111, then Yvette Cooper with 106 and Liz Kendall with 18.
The supporting nominations have no weight in the vote but give an insight into the views of active party members.
Mr Corbyn also has the backing of the UK's two largest trade unions.
All registered Labour Party supporters and affiliated supporters who join before midday on the 12 August can vote in the contest. Voting will begin on 14 August.
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How influential are the unions?
Leadership candidate Andy Burnham has told the Guardian the Labour Party is at risk of splitting because of the provocative language used by supporters of left-wing candidate Mr Corbyn.
Union leader Dave Ward described Blairites in the party as a "virus" to which Mr Corbyn was the antidote.
But Mr Burnham said the comments should sound "alarm bells" to the party of the danger of a return to the early 1980s, when a bitter rift between left-wingers and centrists led to the creation of the Social Democratic Party.
Acting Labour leader Harriet Harman told the BBC that whoever won the contest there "must not and would not be a split in the Labour Party".
"In a hotly contested leadership race stakes run high and things get said which raise the temperature and they shouldn't," she said.
"What we need is a proper debate."
A poll by Research Now found Mr Burnham was the preferred Labour leader among members of the public.
Of the 1,001 people questioned, 30% of those who expressed an opinion picked Mr Burnham as the best leader.
Mr Corbyn and Ms Cooper both got 24%, and 21% chose Ms Kendall.
Olympic silver medallist rower Chris Bartley has announced his retirement.
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Jeremy Corbyn is the most popular candidate for Labour leader among local constituency groups, according to the latest party nomination figures.