Abraham J. Simpson ("Grampa" or "Abe") is a fictional character featured in the animated cartoon television series The Simpsons. His voice is provided by voice actor Dan Castellaneta.

Abraham Simpson is possibly of Irish origin, immigrating to the United States as a child with his parents. Abraham Simpson is estranged husband to Mona Simpson, father to Homer Jay Simpson and Herbert Powell, father-in-law to Marjorie Bouvier Simpson and grandfather to siblings Bartholomew J. Simpson, Lisa Marie Simpson and Margaret Simpson. He is the son of Orville Simpson. He also fathered a daughter by a British lady while in England during World War II.

Abraham Simpson's name derives from Matt Groening's real-life grandfather's first name. However, the writers of The Simpsons were the ones that chose the name, not Groening. Also, one of Matt Groening's sons is named Abraham.

Grampa Simpson is an ancient, grizzled and mostly senile figure who lives in the Springfield Retirement Castle , a sad, lonely place filled with demented, crippled, and depressed old people (a sign near the entrance says "Thank you for not mentioning the outside world").

His rambling stories trail away in forgetfulness and despair:

"You see, back in those days, rich men would ride around in zeppelins, dropping coins on people, and one day I seen J. D. Rockefeller flying by. So I run out of the house with a big washtub and... hey! Where are you going?"

"Anyway, where was I? Oh yeah. I used my washtub that morning to clean my turkey, which back then was called a 'walking bird'. We had walking bird on Thanksgiving with cranberry sauce, potatoes, and stuffing full of gun powder. We also sat around and watched football which back then was called baseball."

A recurring feature is Abe's constant explanation of what happened "in those days":

"We can’t bust heads like we used to, but we have our ways. One trick is to tell 'em stories that don’t go anywhere -- like the time I caught the ferry over to Shelbyville. I needed a new heel for my shoe, so, I decided to go to Morganville, which is what they called Shelbyville in those days. So I tied an onion to my belt, which was the style at the time. Now, to take the ferry cost a nickel, and in those days, nickels had pictures of bumblebees on 'em. 'Give me five bees for a quarter,' you’d say."

"Now where were we? Oh yeah -- the important thing was I had an onion on my belt, which was the style at the time. They didn’t have white onions because of the war. The only thing you could get was those big yellow ones..."

Bart and Lisa dread his occasional childminding sessions; even a phone call has its dangers (" ... and that's everything which happened in my life right up to the time I got this phone call...") -- at least until he falls asleep and leaves them to their own devices. In the meantime, he fills his time with complaining about anything and everything to anyone and everyone he can find.

Abe's age is indeterminate, perhaps inconsistent in the series . This includes his being older or younger than fellow cast member Charles Montgomery Burns. He brags that President of the United States Grover Cleveland (March 18, 1837 - June 24, 1908) spanked him on two non-consecutive occasions (a play on Cleveland's two non-consecutive terms of office). He admits to having "taken a shot at Teddy Roosevelt," (October 27, 1858 - January 6, 1919). He is also known to be a decorated war hero, having paradoxically earned the German Iron Cross during his service in the United States Army -- clearing mine-fields.

Sgt. Simpson was the leader of the Flying Hellfish squad. Among those in his command was Burns. After "liberating" a stash of priceless art from the Nazis, they formed a tontine, and buried the art in a trunk at sea. Decades later, Burns tried to murder Abe in order to get the art. This prompted Abe to violate the tontine because he knews the now-deceased Hellfish wouldn't want Burns to wind up with them. After Abe and Bart get the art back from Burns in a spectacular chase, agents from the United States State Department arrived, and gave the art to their "rightful" owner, a snooty young German aristocrat.

He also claimed to have served on PT-109, where he and two other crewmen beat up John F. Kennedy, thinking he was a Nazi. However, the vast majority of his memories of the past are known to be wildly inaccurate and often physically or historically impossible and thus most likely to be symptoms of his senility. Abe also claims to have served in World War I (1914-1918); however, he was only five or six.

Abe also said that he was in The Wizard of Oz. The legs that curled up when the ruby slippers were removed were his.

There is evidence that Abe was not a kind or caring father to Homer ("Homer, you're dumb as a mule and twice as ugly. If a strange man offers you a ride, I say take it!") Homer does not seem to particularly resent these casual abuses, considering his father's now feeble state.

See: Characters from The Simpsons