Former Everton, Manchester United, and Sunderland boss Moyes lifted the Hammers out of the relegation zone after replacing Slaven Bilic on a short-term contract in November.
But an eventual 13th-placed finish, thanks to seven points from their final three matches, was apparently not enough to earn the 55-year-old Scot a new deal.
In announcing the departure of Moyes on the club website, joint-chairman David Sullivan said: “We are already taking steps to identify and recruit the manager we believe can take West Ham United forward in line with our ambitions.
“We aim to appoint a high-calibre figure who we feel will lead the club into an exciting future for our loyal supporters within the next 10 days.”
It’s a familiar refrain.
Rafael Benitez was top of Sullivan’s wanted list before Bilic got the job. Meanwhile, West Ham were reportedly turned down by Carlo Ancelotti, Ronald Koeman, Sean Dyche, and Paulo Sousa before turning to Moyes.
Sullivan has reportedly already held talks with Shakhtar Donetsk manager Paulo Fonseca. Yet reports emanating from Fonseca’s homeland Portugal claim he has instead opted to stay put with the Ukrainian side and sign a new contract.
Former Manchester City boss Manuel Pellegrini, currently with Hebei China Fortune, outgoing Paris St-Germain coach Unai Emery, and Newcastle’s Benitez — again — have also been linked with the role.
Assistant coaches Alan Irvine, Stuart Pearce and Billy McKinlay have also left their roles.
Ex-Hammers striker Tony Cottee felt Moyes deserved a new contract and hit out at the decision-makers at the London Stadium.
Cottee said: “The guy was brought in to do a job in difficult circumstances. He’s got the results so surely he deserved a chance to take the club forward? I’m disappointed, but not surprised.
“I really don’t know what is happening at my football club, I am so fed up with what is going on.”
Meanwhile, Everton’s summer restructuring is under way after manager Sam Allardyce was sacked and PSV Eindhoven’s Marcel Brands arrived to replace director of football Steve Walsh.
Both departures were expected as the pair paid the price for poor performance on the field and disappointing business off it, after the biggest transfer spend in the club’s history — almost £200m (€228.4m) — backfired.
Brands spent eight years at PSV and signed players like Georginio Wijnaldum, Kevin Strootman, and Dries Mertens relatively cheaply.
He will be tasked with the search for a new manager along with new chief executive Denise Barrett-Baxendale and deputy chairman Keith Harris, whose promotions were only announced on Tuesday evening.
Marco Silva is the favourite to take over after a failed bid to secure him from Watford in November. The Portuguese was sacked in January with Watford stating the catalyst for their slump in results was Everton’s “unwarranted approach” which they felt contributed to a significant deterioration in focus.
It is understood that should Everton ultimately appoint Silva they anticipate having to pay Watford substantial compensation, having had their £12m (€13.7m) offer rejected six months ago.
Brands will have a big say in that appointment and the future direction of the club.
Brands said: “The fantastic passion of the fans for their club, the magnificent history of the club over the years, and the ambition and purpose we have as people tasked with driving the club forward all mean we need to be competing for honours against the Premier League elite.
“It is no straightforward challenge but this must be our motivation each and every day. Now we will look to build something really strong and lasting here at Everton.”