Film historian Virginia Wright Wexman describes Antonioni's perspective on the world as that of a "postreligious Marxist and existentialist intellectual." In a speech at Cannes about L'Avventura, Antonioni said that in the modern age of reason and science, mankind still lives by "a rigid and stereotyped morality which all of us recognize as such and yet sustain out of cowardice and sheer laziness". He said his films explore the paradox that "we have examined those moral attitudes very carefully, we have dissected them and analyzed them to the point of exhaustion. We have been capable of all this, but we have not been capable of finding new ones."
Nine years later he expressed a similar attitude in an interview, saying that he loathed the word 'morality': "When man becomes reconciled to nature, when space becomes his true background, these words and concepts will have lost their meaning, and we will no longer have to use them." One of the recurring themes in Antonioni's films is characters who suffer from ennui and whose lives are empty and purposeless aside from the gratification of pleasure or the pursuit of material wealth. Film historian David Bordwell writes that in his films, "Vacations, parties and artistic pursuits are vain efforts to conceal the characters' lack of purpose and emotion. Sexuality is reduced to casual seduction, enterprise to the pursuit of wealth at any cost."
Antonioni's films tend to have spare plots and dialogue, and much of the screen time is spent lingering on certain settings, such as the seven-minute continuous take in The Passenger, or the scene in L'Eclisse in which Monica Vitti stares curiously at electrical posts accompanied by ambient sounds of wires clanking. Virginia Wright Wexman summarizes his style in the following terms: "The camera is placed at a medium distance more often than close in, frequently moving slowly; the shots are permitted to extend uninterrupted by cutting. Thus each image is more complex, containing more information than it would in a style in which a smaller area is framed ... In Antonioni's work we must regard his images at length; he forces our full attention by continuing the shot long after others would cut away."
Antonioni is also noted for exploiting colour as a significant expressive element of his cinematic style, especially in Il deserto rosso, his first colour film. Bordwell explains that Antonioni's films were extremely influential on subsequent art films: "More than any other director, he encouraged filmmakers to explore elliptical and open-ended narrative".
Film director Akira Kurosawa considered Antonioni one of the most interesting filmmakers. Stanley Kubrick listed La Notte as one of his ten favorite films in a 1963 Poll. Andrei Tarkovsky also listed Antonioni as one of his favorite filmmakers. Miklós Jancsó considers Antonioni as his master. Antonioni's spare style and purposeless characters, however, have not received universal acclaim. Ingmar Bergman stated in 2002 that he considered some of Antonioni's films, including Blowup and La notte, masterpieces for their detached and dreamlike quality, but found the other films boring and noted that he had never understood why Antonioni was held in such esteem.
Ironically, both Bergman and Antonioni died on the same date. Orson Welles regretted the Italian director's use of the long take: "I don't like to dwell on things. It's one of the reasons I'm so bored with Antonioni - the belief that, because a shot is good, it's going to get better if you keep looking at it. He gives you a full shot of somebody walking down a road. And you think, 'Well, he's not going to carry that woman all the way up that road.' But he does. And then she leaves and you go on looking at the road after she's gone."
American actor Peter Weller, whom Antonioni directed in Beyond the Clouds, explained in a 1996 interview: "There is no director living except maybe Kurosawa, Bergman, or Antonioni that I would fall down and do anything for. I met Antonioni three years ago in Taormina at a film festival. I introduced myself and told him that I adored his movies, his contributions to film, because he was the first guy who really started making films about the reality of the vacuity between people, the difficulty in traversing this space between lovers in modern day... and he never gives you an answer, Antonioni – that's the beautiful thing."