On Tuesday, England manager Gareth Southgate announced a 33-man squad, which will be reduced to 26 players for the tournament beginning on June 14 in Germany.
Rashford, 26, has played in 60 England games, scoring 17 goals. However, he has struggled at the club level this season, scoring just eight goals in 42 appearances for United.
“These are difficult calls. With Marcus, I just feel other players in that area of the pitch have had better seasons,” Southgate told reporters.
Shortly after the announcement, Rashford posted an Instagram story featuring the England provisional squad with the caption, “Wishing Gareth and the boys all the best for the up and coming tournament.”
Former Liverpool captain and current Ajax midfielder Jordan Henderson, Chelsea skipper Reece James, and Blues teammate Raheem Sterling also miss out on the squad.
Henderson had a turbulent season, including a short spell at Saudi Arabian club Al Ettifaq before moving to Ajax in January, where he has been sidelined by injuries.
“Henderson’s given himself every chance. The determining factor was the injury he picked up in the last (international) camp,” Southgate added. “He missed five weeks and wasn’t able to get back up to the level of intensity in the game since then. He is a fantastic professional. That was a difficult call to make.”
United’s rising star Kobbie Mainoo has been included in the squad alongside teammates Harry Maguire and Luke Shaw, despite Shaw’s lengthy injury layoff.
England’s all-time record goalscorer Harry Kane will have a formidable supporting cast in Real Madrid’s Jude Bellingham, Manchester City’s Phil Foden, and Arsenal winger Bukayo Saka.
Southgate has also called up five uncapped players: Liverpool duo Curtis Jones and Jarell Quansah, Crystal Palace’s Adam Wharton, Everton’s Jarrad Branthwaite, and Burnley goalkeeper James Trafford.
England will be hoping to go one better after losing the Euro 2020 final to Italy on penalties three years ago.