The Celtic striker, whose Greece team will open the tournament on Friday when they take on co-hosts Poland in Warsaw, believes England are one of four sides with a chance of lifting the trophy on July 1 in Kiev.
England goalkeeper Joe Hart, who was with Samaras at Manchester City before the striker moved to Parkhead, is part of the reason the Celtic star says Roy Hodgson's side cannot be discounted.
"England have the best league and they have world- class players in that league," said Samaras. "I don't know how much Fabio Capello leaving will change things, in terms of the chemistry of the team. England always have the quality and work hard.
"Joe was a teenager when I was at Manchester City. He came to the club just after I did and had great potential. You can never rule out England – they are always in the four favourites, England, Germany, Italy, Spain.
"But they always seem to have bad luck in the later stages of tournaments. In the 2010 World Cup finals they suffered Frank Lampard's disallowed goal against Germany and in the other Euros, they were close but lost on penalties."