Patti Mayonnaise is the love interest of Doug Funnie of the series Doug, both the original Nickelodeon series and Disney series.
Throughout the show series he has a secret crush on Patti with many of his Smash Adams and Quailman daydreams involve her as the damsel in distress.
They’re best friends, and they usually get along well, but they have had conflicts before; however, they always sort it out by the end of the day. The two won't hesitate when it comes to working together; like in Doug and Patti P.I.
When they first met, Patti was exceptionally nice and forgiving to Doug.
The first time her affections for Doug were in Doug to the Rescue.
In Doug's Magic Act, after getting handcuffed to one another, making her miss own plans, Patti tells Doug she is not going to talk to him after they miss getting to the magic shop in time before it close to get the handcuffs take off. She also tells him he is very selfish. However, Doug, feeling guilty, opened up to her and says that she is all he thinks about. He realises his mistake and blames himself. Patti forgived him and tells him he is her favorite person to be around. They then hold hands.
In “Doug & Patti Sittin' in a Tree”, Patti asked Doug out to the movies and afterward, the two consider that it was a date, but try to laugh it off. They almost kiss, but Patti felt somewhat scared as if she seems to have feelings for Doug.
In “Doug Throws a Party”, when Doug refuses to take off Connie's hat because he doesn't want to embarrass her, Patti compliments him for his decision by saying that it was "the most grown-up thing anybody's done tonight", and that his decision was sweet of him, and she kisses Doug on the cheek.
In the Disney run of Doug added Guy Graham, who also a crush on Patti.
In Doug's Marriage Madness Patti asks Doug out on a date-date.
In Doug's 1st Movie, Doug continued to compete with Guy for Patti's affection; when Doug fails to show up at Swirly's to discuss the dance, and when he revealed that he had not caught the monster Herman Melville (despite having done so, to keep Herman's existence a secret), Patti becomes resentful of Doug in favor of Guy.
This rivalry comes to a head when Doug revealed to Patti that Guy fabricated an article where Mr. Bluff was revealed to have killed Herman Melville. Patti dumps Guy (by literally by pushing him in the lake) and goes out with Doug - the date-date she had request in "Doug's Marriage Madness". By the end of the movie, Patti is seen dancing with Doug. (Doug remark that he and Patti danced "for quite a while".)
She is voiced by Constance Shulman.