Shillingford, 30, and team-mate Marlon Samuels were both reported to the ICC for suspected illegal actions during last month's Test series in India.
Meanwhile, Samuels, 32, has been banned from bowling his quicker deliveries.
Shillingford's arm was found to extend more then the permitted 15 degrees for his off breaks and doosras.
Samuels exceeded the 15-degree limit for his quicker balls, but he is allowed to continue bowling his standard off breaks.
A batting all-rounder, he has played for the Windies as a specialist batsman before now, although Shillingford - a specialist bowler - now faces withdrawing from international cricket until he remodels his action.
The pair have 14 days to lodge a written appeal to the ICC, although West Indies are currently in the middle of a Test series in New Zealand.
Shillingford and Samuels both played in the first two Tests, although Samuels did not bowl.
The third Test begins in Hamilton on Thursday, with one-day and Twenty20 internationals to follow.
Both players have previously been suspended from bowling in international cricket for illegal actions.
However, they were allowed to resume bowling after undergoing remedial work and further testing.
Samuels was banned from bowling in February 2008 because his arm extended more than the permitted 15 degrees for off-breaks and quicker deliveries.
Although the Jamaican continued to play as a batsman, he did not resume bowling in international cricket until September 2011, having served an unrelated two-year suspension from cricket between May 2008 and May 2010 for passing information to a bookmaker.
Shillingford, from Dominica, was reported after his international debut in November 2010 and banned a month later when his average elbow extension was found to be 17 degrees. He was cleared to return in June 2011.

New York City's new Mayor Bill de Blasio refused to join the city's annual parade, and Guinness has withdrawn its sponsorship.
Parade organisers said gay groups are not prohibited but may not carry identifying banners.
Boston Mayor Martin Walsh also skipped his city's parade on Sunday.
Mr de Blasio has said he would not join the parade in protest against its long-standing policy of excluding gay Irish groups from marching openly.
The New York mayor played host to Irish Prime Minister Enda Kenny for a St Patrick's Day breakfast before the parade.
Mr Kenny joined the procession down Fifth Avenue in New York City's Manhattan borough on Monday, after saying the holiday was about Irishness, not sexuality.
On Sunday, Irish beer brand Guinness said it was dropping its participation in the New York parade.
"Guinness has a strong history of supporting diversity and being an advocate for equality for all," the brand said in a statement issued by parent company, Diageo.
"We were hopeful that the policy of exclusion would be reversed for this year's parade."
The firm pulled any promotional materials that were not already printed, although the beer maker had already made a payment to parade organisers, spokeswoman Alix Dunn said.
Some gay and lesbian groups protested along the parade route on Monday, while a plan to dump Guinness beer from the shelves of the Stonewall Inn, the birthplace of the gay rights movement in New York City, was cancelled after the company pulled out of the parade.
New York's parade draws more than one million spectators and about 200,000 participants during the St Patrick's Day holiday.
On Friday, two other major beer brands, Boston-based Sam Adams and Heineken, also dropped parade sponsorships.
In Boston, Mr Walsh, the first Irish-American Boston mayor in 20 years, said: "So much of our Irish history has been shaped by the fight against oppression.
"As mayor of the city of Boston, I have to do my best to ensure that all Bostonians are free to participate fully in the civic life of our city."

Anglesey council's contract for 17 toilets ends in 2017 and they face being scrapped due to budget cuts.
A letter has been sent to councils to see if there is interest in taking them over from 1 April.
Councillor John Roberts said: "We don't want to reach a situation where we'll have to close toilets and sincerely hope that we can find a solution."
West Indies off-spinner Shane Shillingford has been suspended from bowling in international cricket by the International Cricket Council (ICC).
[NEXT_CONCEPT]
The world's largest St Patrick's Day parade has kicked off under a cloud of protest against the organisers' refusal to allow gay groups to march openly.
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Public toilets on Anglesey are being offered to town and community councils in a bid to stop them being closed.