When it comes to the smartest Avenger, it has to be Iron-Man that is considered to be the most intelligent. While he and Bruce Banner are likely on a level when it comes to their scientific knowledge, the fact that he retains that when turning into Iron-Man just edges him above the big green guy.
Rocket famously said that Tony Stark was only smart for Earth, and he's proven time and time again that he's the smartest character in the MCU. He can think his way out of almost every problem, create a gadget out of basically anything, and is now the official leader of the Guardians of the Galaxy.
Scientific aptitude and knowledge. Apart from his physical abilities, Peter is an intellectually-gifted scientific teen genius and has a prodigious aptitude in the physical sciences, with a high IQ level of around 150.
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Who has more IQ Batman or Iron Man?
However, his engineering acumen does make him smarter than Batman in at least one place, so it does count. Batman's intelligence is more well rounded, but Iron Man has him beat in some particular areas.
While extremely strong, Thor is also characterized as being somewhat limited intelligence-wise, as he easily falls for various schemes like in the tale of Utgarda-Loki.
Thanos is known for being superlatively powerful, but he's also as intelligent as they come. Thanos was educated on Titan among his fellow Eternals and learned many secrets of the universe in his travels. Iron Man is intelligent, but Thanos is smarter than Iron Man could ever be.
Many things can be said about Amadeus Cho. He's the seventh-smartest person in the world, he's Korean-American, he's friends with the Hulk—and he even became the Hulk himself. Cho's "totally awesome" intelligence gets him into trouble as often as it gets him out of it.
Ultron can use his incredible artificial intelligence to access every piece of data available on Earth. He cannot only search the internet with astonishing quickness, but also use it to send his consciousness to other robotic bodies, making him nearly indestructible.
While Steve Rogers gets the title of the oldest human avenger, Thor Odinson, as the mighty Asgardian God of Thunder, has a much longer life span than any of his Earth-born friends.
Thanos went to a craftsman for his Gauntlet, implying that he isn't the ridiculously brilliant engineer Tony is (he built a super-suit in cave using a missile!). If it had been Tony, I guarantee he would have built it on his own.
While he's known for his powers, he's also one of the most intelligent, crafty beings in the universe. He's outsmarted gods, the Elders of the Universe, and cosmic beings. Batman is good but Thanos is out of his league. Thanos is smarter than Batman and, most importantly, a lot craftier.
Marvel has seemingly confirmed that Doctor Doom is smarter than Iron Man. In Avengers: War Across Time #2, the team visits the Fantastic Four's headquarters in the Baxter Building, seeking a way to travel through time–and there they find Doctor Doom's infamous time platform.
High Intellect: Odin is extremely intelligent and clever, as even Mimir, the smartest being alive in all the Nine Realms, acknowledged his cleverness, saying that he is almost as clever as he believes himself to be.
Thor Odinson, sometimes referred to by his title as the God of Thunder, is a fictional character portrayed by Chris Hemsworth in the Marvel Cinematic Universe (MCU) media franchise, based on the Marvel Comics character of the same name and the Norse mythological god of the same name.
Genius Level Intellect: Batman is noted as having an I.Q. of 1045. Martial Arts: Batman is a master of martial arts from across the universe, able to catch the original Batman off-guard and defeat him with a single blow; he is also known to incorporate psychic attacks into his fighting style.
The original question was: “Is Tony smarter than Bruce Banner?” Banner is the smarter “Smart Guy.” The writers/directors/producers answered this in Age of Ultron and Endgame.
Joker's intelligence (ie. is he smart?) So in most of Joker's history he's characterized as being highly intelligent. In TDK he was always the smartest guy in the room, hatched an incredibly complex scheme against all his foes, and nearly won if not for losing a fist fight with Batman.
