Season 3

Mr. Wilson accidentlly gets a space helmet that belongs to Dennis stuck on his head.

Dennis and Mr. Wilson camp out on a moutain so that Dennis can join the Junior Pathfinders club.

Henry gets a ticket for walking on the grass in the park. When Mr. Wilson hears about it he thinks it isn't fair, So he convinces Henry to go to court and contest it.

Dennis is using numbers for a football play which is the combination to Mr. Wilson's safe, So Mr. Wilson and Henry get Dennis so confused that he forgets the combination. Then Mr. Wilson forgets it. Now they are in a real mess because Mr. Wilson has something very important locked in the safe. So Mr. Wilson tries everything including trying to hypnotize Dennis so he can remember the combination. He ends up hypnotizing himself and remembers the combination at last.

Mr. Wilson and Henry both invest in a house that is known to be a haunted house.

Dennis' school is putting on a play which Mr. Wilson ends up being in (not by choice) because him and Tommy (who is also in the play) get handcuffed together before the play starts.

Mr. Finch is having a contest that when the fifty-thousandth customer walks in his store they will win 5 minutes of free shopping of which Mr. Wilson is determined to be the one who wins.

Mr. Wilson coaches Dennis' Pee Wee League baseball team because Dennis' dad (who originally was the coach) got sick.

Mr. Wilson wants to represent Scotland for Dennis' School

The school test scores mistake Dennis as a genius.

Mr. Wilson tricks Dennis into taking a silver coin that says GOOD LUCK and a horseshoe on it instead of 50 cents that he owes him for cutting his lawn. Mrs. Wilson is very angry with him about it. So, she and Alice start a scheme of their own by making lucky things happen to Dennis all day. Mr. Wilson soon starts to believe that the coin was lucky after all and is sorry he ever let it go. He then realizes that it was all a charade to teach him a lesson.

Dennis, Henry and Mr. Wilson go out in the woods and cut down a big Christmas tree which ends up getting almost destroyed by the time they get it home.

Dennis opens a bank account at the bank of where Mr. Wilson works at and causes a lot of chaos at the bank.

Dennis' cub scouts are putting on a circus of which Mr. Wilson is the Lion in the circus, which is suppose to be a secret from everyone.

Mr. Wilson holds a bird lovers session at his home Where a woman does bird calls that sounds just like a bird.

Mr. Wilson agrees to give Dennis his magnifying glass if he doesn't talk around him for the day.

Dennis is put on the spot when he askes both Mr. Wilson and Mr. Mactavish to represent Scotland in his school project.

Dennis enters his frog in the frog jumping contest with Mr. Wilson as his partner who has a bet with Sgt. Mooney that Dennis' frog will beat his.

Mr. Wilson gives Dennis a Gold watch in his will. Soon after that Mr. Wilson begins to feel old and is convinced that he has short time to live.

Mr. Wilson's Uncle comes to visit him and convinces him that he isn't in shape, so he starts a physical fitness program and forces Mr. Mitchell and Mr. Wilson to be in it.

Mr. Wilson plans to have a quiet evening at home, but his plans change when Henry needs a sitter for Dennis.

Mr. Wilson gets his wallet taken by a pick pocket, So Dennis and Tommy try to find the crook for the police.

Mr. Wilson hires a housekeeper for Mrs. Wilson but soon regrets it when the housekeeper tries to tell Mr. Wilson what he can and can't do in his home. Mr. Wilson then tries to get rid of her.

A big shaggy dog followes Mr. Wilson home and Mr. Wilson tries to get rid of it.

Dennis does a documentary film of the town for a school project with Mr. Wilson's help.

Mr. Wilson takes Dennis and his friends up to the lake and back in an old car. Mr. Wilson then gets elected president of the Horseless Carriage Club.

Mr. Wilson attempts to start a fire like the pioneers did for Dennis' Junior Pathfinders club and nearly burns down the place.

Mr. Wilson buys a treasure chest at an auction thinking that it has buried treasure in it. Mr. Wilson later discovers a treasure map drawn by Dennis. Although Mr. Wilson thinks the map is authentic so he plans to take a trip to the island and dig for the treasure.

Dennis convinces Mr. Wilson to go to the Dentist for his tooth because Dennis thinks he can get a basketball from the Dentist until he learns that the Dentist only gives away prizes to child patients.

Mr. Wilson thinks his next door neighbor is the stocking bandit and tries to prove it.

Mr. Quigley coaches Dennis' baseball team with help from Sandy Koufax.

Dennis helps Mr. Wilson's Uncle Ned plant flower bulbs in his yard in order to get out of playing house with Margaret Wade.

George Wilson's brother John Wilson comes to visit, only he has trouble working without his old cushion.

Dennis and his friends win John Wilson a chicken, which John wants to cook for dinner and the children try to talk him out of it.

Dennis is all set for a big day. He is scheduled to have a fight with Gifford - the school bully.

Dennis wants to join an older boys club, but in order to do so he has to take an initiation.

The Neighborhood Community puts on a carnival in the park with different winning contests to participate in.

Mr. Wilson is doing a magazine article on voodoo, Dennis gets the wrong idea and tells the whole neighborhood that Mr. Wilson is a Witch Doctor, Soon the whole town gets the wrong idea about Mr. Wilson.