Miss Yvonne (real first name: Yvonne) was a frequent visitor to the playhouse; obsessed with fashion and beauty; commonly proclaimed as "The Most Beautiful Woman in Puppetland" despite some casual viewers thinking the opposite of her beliefs, although Pee-Wee and his Playhouse characters such as Chairry often agree with her views of being the most beautiful (probably to be polite). She symbolizes the common "girl next door" trope. She is usually dressed in gaudy prom/bridesmaid-type gowns with many petticoats and crinolines, has her hair in a bouffant, and wears white high heels.

She is often paired with Cowboy Curtis, who does things together with Herman, and in one episode asked out Cowboy Curtis on a date, where Herman helped Cowboy Curtis prepare for it by first going on a practice run with Cowntess. Despite this, she had crushes on a lot of men during the show, including Conky Repairman Johnny Wilson, Tito, Ricardo and Fireman Frank, though she never pursued a committed romantic relationship with any of these men. She also seems to occasionally show feelings for Herman himself, and he with her based on his interactions with her, even though the latter acts like a spoiled brat most of the time and not a mature man. In the fan fiction Wedding at the Playhouse, she and Herman finally get married and later have a daughter whom they name Paprika (after one of the daughters of Pepper and ASIMO, two well-known robots).

She is the Fuschia Ranger of the Puppet Rangers, a group of Power Rangers that serve as auxiliaries to the Power Rangers Zeo.

On a few occasions on Playhouse, Yvonne has shown that she can act very manipulative towards Herman, usually in an attempt to influence him into making a decision that will likely go in her favor, resulting in his anger and some sharp rebukes. The two main instances of this misbehavior are Luau for Two and Heat Wave.

Her first name being "Yvonne" was confirmed by Chicky Baby when she thanked her in Luau for Two for styling her hair ("Thanks, Yvonne! It's out of sight! Perfect for my date tonight!"). This occurs again in Conky's Breakdown

In Ants in Your Pants, she calls Conky her favorite robot, and in Fire in the Playhouse she calls him "my darling".

In the episode Miss Yvonne's Visit, it is revealed to us that while she has great beauty and a warmhearted image, Yvonne actually is a terrible, slovenly houseguest—her dresses are strewn about all over the place and she does not clean up after herself. She also has several moving men/bodyguards employed in her service (including a man resembling Ricardo who is played by actor Vic Trevino), and whenever she travels anywhere she literally takes her makeup and beauty supplies with her to maintain her famous beauty.

The character was played by Lynne Marie Stewart, who had also worked with Paul Reubens in the film Pee-Wee's Big Adventure, although not as Miss Yvonne. In the film, she played an actress who was frustrated at trouble on the set over a pretentious child actor who has Pee-Wee's bike. Another film she did was the 1987 film The Running Man, starring Arnold Schwarzengger. Somewhat akin to Miss Yvonne, Stewart played an audience member who gushed over the host and selected a hockey-themed "Stalker" named "Subzero" to try and kill Arnold. Subzero was played by Professor Toru Tanaka, who also played Francis' butler in Pee-Wee's Big Adventure.

The character first appeared in The Pee-wee Herman Show, also played by Stewart.

Miss Yvonne is a middle-aged woman (a 60-something-year old woman in current times) with big, bright, beautiful brunette hair. Her normal attire consists of a pink or blue sleeveless dress and slip-on shoes or high heels.