Horrid Henry's Wedding is the forty-fourth episode of Series 1.
The episode starts with Henry refusing to put his outfit on for Polly and Paul's wedding at a shop. Mum, Paul, and Polly eventually then forced him to put it on. Back at home, Henry then makes Fluffy tear up his outfit. While watching Mutant Max, Mum interrupts Henry by cutting off the TV, angry because she found out about the ripped clothes. Unfortunately, Mum had one more pair, and is pink, making Henry say "No!!!"
Next morning, everyone put on their outfits for the wedding, all except Henry. Mum and Dad chased Henry around the house and pulls him from under his bed saying "It's Not Fair!" and makes him wear his outfit. It was raining outside everyone panicked except Henry. The family head off in their car but ran into some traffic. When they got there, Henry lands in the puddle and his family were covered in it. Paul warns Henry that if he tries to ruin Polly's life, he'll get really really angry.
The wedding begins Henry and Peter holding two rings on each pillow until Henry steps the part of Polly's dress at the back, she tries to control herself and kisses him on the forehead. Henry laughed when Paul's full name is Peregrin but he tells him to be quiet. Henry plays around with the ring but loses and gives Polly another ring which gave her a fright. Outside, Henry ruins every shot and Dad takes him away.
While Paul gives a speech to everyone, Henry sneaks off and eats every bite of the cake. Paul chases him around and hits the cart and heads straight for Polly and cries. When Mum tells Henry off for ruining Paul and Polly's wedding, she says this is positively the last wedding she's ever taking him to . Henry was thrilled and thinks this is the best day of his life and shouts "YES!" ending the episode.
- , her lips were pink, but in the next shot, her lips are plain, just like her original appearance when she's normal.
- When Mum taps Henry on the shoulder at the end, Henry's suit is blue like the original one that Fluffy destroyed, not pink.
- In this episode, Peter says that Polly is his favourite cousin. But in Horrid Henry Eats Out, he says that Stuck-Up Steve is his favourite cousin. This could hint that Peter loves everyone in the family.