The 39-year-old is Pakistan's leading run-scorer in Test cricket, having made 9,977 runs in 115 Tests since his international debut in 2000.
He has an average of 53.06, with 34 centuries and a highest score of 313.
"I will be retiring from international cricket after the West Indies series with my head held high," said Younus.
"I think this is the right time as every sportsman has to take this decision in his career."
He previously captained Pakistan in all three formats of the game and led them to their only World Twenty20 title in England in 2009. He also had a spell in county cricket with Yorkshire in 2007.
Younus' announcement comes two days after Test skipper Misbah-ul-Haq, 42, announced that he will also retire from internationals after the Windies Test series.
The veteran duo were also named among Wisden's five Cricketers of the Year last week.

The government originally owned a 41% stake after ploughing £20bn into the bank during the 2008 financial crisis.
It started selling Lloyds shares in 2013, and the latest sale means it has now raised more than £8bn.
Last weekend, David Cameron said the Conservatives would offer up to £4bn of Lloyds shares to private investors if he won the general election.
The prime minister said it would "help us recover billions more to pay down the national debt". The Labour party said the Tories had announced the plans several times before.
In the latest sale, the government sold 742 million shares which, at Thursday's closing price, would have raised £586m for the Treasury. The actual total may be slightly lower as the government would have sold its shares throughout the day, during which Lloyds shares rose steadily in the afternoon to hit a closing high of 78.99 pence.
The sale means the government's shareholding has been reduced by another 1%, and is now down to 20.95%.
"Today's announcement shows the further progress made in returning Lloyds Banking Group to full private ownership and enabling the taxpayer to get their money back," a statement from Lloyds said.
"This reflects the hard work undertaken over the last four years to transform the group into a simple, low-risk and customer-focused bank that is committed to helping Britain prosper."

The 16-year-old was reported missing on 19 February. Body parts were found at a house in the Barton Hill area of Bristol on 2 March.
Organisers said although the walk "won't bring Becky back" it will help "give this beautiful young girl the send-off she deserves".
Becky's stepbrother Nathan Matthews, 28, has been charged with her murder.
Friends have sold wristbands, T-shirts and balloons to help support her family.
The walk started at 11:00 GMT on The Centre and is making its way to Castle Park where balloons are due to be released in her memory.
Earlier this week, Mr Matthews, from Warmley, Bristol, appeared by video link at Bristol Crown Court.
He has yet to enter a plea to the charge and was told a provisional trial date had been set for October.
His girlfriend, Shauna Hoare, 21, who is charged with perverting the course of justice, also appeared by video link.
Four other defendants have been charged with assisting an offender.

Bowe, 30, scored the second of Ireland's tries in Saturday's 29-15 win over South Africa at the Aviva Stadium.
He has won 55 caps for Ireland, scoring 27 tries, and has made 124 appearances for Ulster, scoring 48 tries.
Earlier this week, the IRFU confirmed that Rob Kearney had also signed a new three-year deal to stay with Leinster.
Bowe made his competitive debut for Ulster against Connacht in April 2004 and enjoyed a spell with the Ospreys, before returning to his home province for the 2012-13 season.
He made his Ireland debut against the USA in November 2004 and has twice toured with the British and Irish Lions.
The Monaghan man played in all three Lions Tests against South Africa in 2009, and in two Tests in Australia in 2013.
He was a member of Ireland's 2009 Grand Slam-winning team and was named Six Nations Player of the Championship in 2010.
"I'm delighted to have signed a new contract with the IRFU and Ulster," Bowe said.
"It is an exciting time for both the province and the national team and I hope to play a part in achieving success on both fronts in the years to come."
Pakistan batsman Younus Khan has announced he will retire after their three-match Test series against West Indies, which starts on 22 April.
[NEXT_CONCEPT]
The government has sold more shares in Lloyds, raising about £586m and taking its stake in the bank to below 21%.
[NEXT_CONCEPT]
Hundreds of people are taking part in a fundraising walk in Bristol to remember Becky Watts who was killed last month.
[NEXT_CONCEPT]
Ireland winger Tommy Bowe will remain with Ulster until at least June 2018 after signing a new three-year contract with the IRFU.