The club announced that the East Stand Entrance at Old Trafford had been 'dressed appropriately' as a tribute to the Queen's 70 years on the throne.
As well as that, United have said that the Megastore, Red Caf and Museum will be closed on Monday and will re-open on Tuesday, September 20.
United posted a statement on the club's website, which included: “The club recognises her immense contribution to public life, including sport, both here in the United Kingdom, across the Commonwealth, and around the world.
“Her Majesty was a great supporter of football, having seen every World Cup since it's inception, including England's 1966 triumph at Wembley Stadium. She also shared her appreciation for the success and impact of our Lionesses during this summer's Euros, championing the women's game as much as the men's.
“We thank our fans for the respect that has been shown at both UEFA Europa League matches, and in particular, the brilliantly observed minute's silence prior to our match against Real Sociedad on the evening of Queen Elizabeth II's passing.
“Manchester United sends our deepest condolences and heartfelt sympathy to King Charles II, The Queen Consort and the wider The Royal Family.”