The 83-year-old, who has Kes, Cathy Come Home, and I, Daniel Blake among his directing credits, described the genre as "boring" and "nothing to do with the art of cinema".
He told Sky: “I find them boring. They’re made as commodities… like hamburgers… It’s about making a commodity which will make profit for a big corporation – they’re a cynical exercise.
"They’re a market exercise and it has nothing to do with the art of cinema.”
Loach's words come after Coppola and Scorsese slated the Marvel movie franchise which has produced box office smashes such as Avengers: Endgame, the highest grossing movie of all time.
Earlier this month, Scorsese dubbed the films as "not cinema" and referred to them as "theme park" movies.
Coppola went on to say that Scorsese was right, telling reporters at the Festival Lumière in Lyon last Friday: “When Martin Scorsese says that the Marvel pictures are not cinema, he's right because we expect to learn something from cinema, we expect to gain something, some enlightenment, some knowledge, some inspiration.
“I don't know that anyone gets anything out of seeing the same movie over and over again.
“Martin was kind when he said it's not cinema. He didn't say it's despicable, which I just say it is.”
Guardians Of The Galaxy writer and director James Gunn said he was "saddened" to see Scorsese criticising films he hadn't seen.
He wrote in a tweet: "Martin Scorsese is one of my 5 favorite living filmmakers. I was outraged when people picketed The Last Temptation of Christ without having seen the film. I’m saddened that he’s now judging my films in the same way."