Originally I was going to try to make a top 10 list but I encountered the problem of some characters being smarter than others when it comes to certain fields. For example; Robin vs Franky. How would you rank these two in terms of intelligence? The thing is, when it comes to technologically speaking, Franky is far superior.
He made the blueprints for the Sunny, he turned himself into a cyborg while on the verge of death, and he made the Franky Shogun. Purely technologically wise, he’s probably the 2nd-4th smartest man in the world. But when it comes to rational thinking or history, Robin certainly has him beat.
She’s definitely the best rational thinker on the Straw Hat Crew, she’s the only Oharan left (meaning the only one capable of reading the Poneglyphs), and she’s incredibly knowledgeable when it comes to the world of One Piece as a whole. So as you can see, ranking these two in terms of intelligence could become rather complicated, and that was the problem of the list overall. So I decided to just create a few separate lists for the different categories of intelligence; Technological, Medical, and Rational/Strategical.
Technological
1 – Dr. Vegapunk
Undoubtedly the smartest man in the world. He’s been stated to be the smartest man several times and it was stated that the thoughts going through his head are 500 years ahead of the present. He figured out how to give objects Devil Fruits, he created the Pacifista (and gave them Kizaru’s lasers), he created artificial dragons, he discovered the uses of Sea Stone, and he helped discover the lineage factor.
2 – Vinsmoke Judge
Judge’s field of expertise is genetics. Judge worked with Vegapunk over 20 years ago and together they were able to discover the lineage factor, Judge created cloning technology so great that even the Yonko Big Mom wants it for herself, and Judge was so skilled with genetics that he was able to genetically modify his own children; giving them exoskeletons that made them bulletproof, combustion/light powers(?), electricity powers, a metal arm or something(?), poison consumption and nullification, and superhuman strength and speed.
3 – Caesar Clown
Another great scientist who worked with Vegapunk. His field of expertise is chemical weapons. He was able to temporarily turn children into giants, he made weapons potent enough to nearly destroy the Minks, he created Smiley, figured out how to abuse Devil Fruit reincarnation, he’s capable of making weapons so devastating that Bege recruited him to take down Big Mom, and he made SAD.
4 – Franky
Franky is a technological genius, and although he may not be as good at genetics or chemicals as Judge and Caesar are, when it comes to robotics and engineering, he’s second only to Vegapunk in my opinion. As I stated earlier, he built the Sunny, he built his only cyborg body, and he built the Franky Shogun.
5 – Tom
Tom was the man who taught Franky everything he knows about being a shipwright. He was able to build the sea train within a few years and he built the Oro Jackson, which Pirate King Gol D. Roger conquered the Grand Line on.
Medical
1 – “Surgeon of Death” Law
Undoubtedly the best Surgeon in the World; with the power of the Ope Ope no Mi, there’s no surgery he cannot complete. Hell, he can even make people immortal at the cost of his own life. He saved Luffy’s life after Marineford and his fruit is generally regarded as one of the most valuable in the world because of it’s astonishing capabilities.
2 – Crocus
The Pirate King’s Doctor. We don’t know much about Crocus’ doctoring abilities other than that he was so great in the medical field that the Roger Pirates sought him out for his skills and he was able to hold back Roger’s incurable disease for as long as he possibly could have and that he was treating Labooon.
3 – Dr. Kureha
When it comes to pure experience, Dr. Kureha has got everyone else in the world beat. With her 100+ years of medical experience, she could easily cure what others thought to be incurable. She taught Chopper everything he knows about doctoring and honestly, I think she still beats post-timeskip Chopper out when it comes to the medical field.
4 – Chopper
He was taught by Dr. Kureha herself and he’s the doctor of Monkey D. Luffy – Future Pirate King. His dream is to one day become the greatest doctor in the world, capable of curing any disease, but for now i’m putting him in 4th. Post timeskip i’d say he’s rivaling Dr. Kureha in skill, but I honestly can’t see him being above her with the insane amount of experience she has.
5 – Dr. Hogback
A renowned doctor around the world. He was skilled enough to be recruited by 320,000,000 million belli man – Gekko Moriah. Over his years working with Moriah, he reanimated hundreds of corpses and even worked to fix the body of the continent puller Oars. Pre-timeskip he might be above Chopper but honestly I think Chopper has surpassed him after his timeskip training.
Rational/Strategic
1 – Clover
The greatest scholar of the Oharans. With his guidance, the scholars of Ohara were able to figure out the existence of the Ancient Kingdom, their war with the World Government, and likely many other mysteries of the Void Century and the years around it. Archaeologically speaking, Clover is the smartest man in One Piece (with exception to EoS Robin most likely).
2 – Sengoku/Tsuru
The great mastermind strategists behind the Marineford War. Without them calling the shots from behind the front line, that war may have ended very differently.
3 – Benn Beckman
Benn Beckman is stated to be the smartest man from the East Blue, which ranks him above Kuro and Nami. We haven’t seen him much so we don’t know much about just how smart he really is, but I think it’s safe to say he may be the strategist of the Red Hair pirates, playing a Nami role of sorts.
4 – Sir Crocodile
Crocodile is, to say the least, extremely savvy. He knows what the fuck he’s doing. He’s extremely knowledgeable of the One Piece world due to the fact that as a rookie he made it far enough into the Grand Line to fight Whitebeard himself, and although he lost that fight and retreated back into Paradise, he certainly learned a lot from that journey and from his time as a Shichibukai. He was smart enough to assemble his own organization of assassins and bounty hunters in a scheme to take down an entire country and he knew about the Ancient Weapon Pluton and the fact that it’s located on the island of Alabasta.
5 – Nico Robin
Archaeologically speaking, Robin is likely the second smartest character in One Piece, only behind Clover. She’s discovered many Poneglyphs along her journey and likely knows pieces of history that are very uncommon knowledge. Putting her above Kuro may be a stretch to some, but while Kuro certainly has her beat on the whole scheming part, Robin has him beat in general knowledge of the One Piece world and its history.
*List by Pirate-King-Ace