Big Mouth Wiki
How come in all these videos puberty for boys is like the miracle of ejaculation and for girls we're just a yarn ball of aching tubes?
—Jessi Glaser in Ejaculation

Jessica "Jessi" Cobain Glaser is one of the main characters of Big Mouth. She is a sarcastic, popular, and intelligent 13-year-old girl with physical/emotional development, who goes to Bridgeton Middle School, where she's friends with Nick, Andrew, Jay, Missy, and Matthew. As of "Everybody Bleeds", Jessi started puberty and got Connie as her hormone monstress. She is voiced by Jessi Klein.


Birth & Childhood

Jessi Glaser was born on April 16th, 2004 to Greg and Shannon Glaser and grew up with her Jewish family in a suburban house in Westchester, New York.


As a 12-year-old girl, Jessi went to Bridgeton Middle School, where she was friends with other students such as Nick, Andrew, Jay, Missy, and Matthew. Jessi was a star student, who was known for being a very outspoken and intelligent girl, who became the captain of the debate team. Jessi debated social and political issues such as gender inequality and considered herself a feminist. Jessi lived a stable family life and never got in trouble with her parents. In fact, she got along with both her mom and dad quite well and saw them more as friends than anything. At this time, Jessi's life was going great and nothing was standing in her way of reaching a future of success and happiness.

In "Ejaculation", Jessi and her aforementioned friends went to the school dance as a group (sans Missy and Matthew) and she had a pretty great time there. However, when she saw how Nick was dumped by his date, Olivia, she felt bad and went to console him when he ran out of the gym, crying. Jessi was a very kind and supportive confidant, even if she did feel the need to say "I told you so." When they had this conversation, Nick made a move on Jessi and Jessi responded by kissing him. This was Jessi's first kiss and it would soon become her first relationship.

In "Everybody Bleeds", Jessi was trying to decide what to wear on her field trip to The Statue of Liberty and her mother suggested she wear white shorts. When Jessi got to school to see Nick again, Matthew pumped them for confirmation on whether they were a thing or not and the two decided that they were officially a couple. As a couple, the duo had the privilege of sitting in the back of the bus with all the other couples such as Devin and DeVon.


In "Everybody Bleeds", Jessi was surprised by her pants getting stained with a flood of blood during her visit to The Statue of Liberty. She had her first period. It was at this moment, Jessi realized that for her, the age of puberty had begun and her childhood had officially ended. Jessi went to hide in the bathroom, while Andrew helped to get something to absorb her blood. All Andrew could get her was a commemorative 9/11 quilt. When Jessi went home, she burst into tears and told her mom everything that happened. When her mom left to get her some tampons, Jessi was visited by Connie, the hormone monstress, who told her that her life was going to change forever. The first thing Jessi did when her mom came back was furiously scream at her to "Get the hell out" and even addressed her as "Shannon" instead of "Mom".

At this time, Jessi's family would soon fall apart as well, where her once functional family rode a downward spiral into becoming a hostile warzone where serenity occurred in seldom arguments were the norm. Jessi's mother was unfaithful in her marriage (having had an affair with a local cantor) and her father has a severe dependency on drugs, particularly marijuana, which has caused Jessi to "act out" in a number of ways, including her on-again-off-again relationship with Jay Bilzerian and attempting to flee her old life to run away with him, because she doesn't like her life at the moment.

This had gotten extremely worse because her dad Greg got together with a cheese sample girl named Kaitlyn. Her dad was in a disgusting flat and Jessi thought it was unpleasant just to be there. Jessi had a mental breakdown when Caitlyn had announced that she and Greg are going to have a baby together and Jessi nicknamed it 'the cheese baby'.


Jessi is a somewhat tall redhead with red hair that is usually tied in a ponytail with bangs hanging over her forehead, brown eyes and she frequently sports deadpan expressions. Although, she is more physically developed than some of her peers (particularly Missy Foreman-Greenwald), she is perpetually insecure of the small size of her breasts, particularly in comparison to Fatima, the romantic protagonist of The Rock of Gibraltar. She is almost always seen wearing a lavender-colored blouse on top. bright crimson leggings and black shoes.


Jessi is an intelligent girl with a dry sense of humor, although despite her negative attitude, she's very likable and shows strong affection towards her friends (despite that she might poke fun at them from time to time). She has strong feminist views and stands up for what she believes in. She fears looking weak or wrong and sometimes lies so that people don’t look down on her. She is in recovery from depression, as well as issues surrounding her family, and attends regular sessions with a therapist.

Hormone Monsters


  • Jessi started puberty in "Everybody Bleeds", where she got her first period, first got Connie as her hormone monstress, and immediately started hating her mother for no reason.
  • In "The New Me", it was revealed that her full name is "Jessica Cobain Glaser". This could mean that one or both of her parents were fans of the late musician Kurt Cobain.
  • In "Super Mouth", it was mentioned that Jessi's birthday is April 16th. Jessi officially turned 13 earlier that year same in "I Survived Jessi's Bat Mitzvah". Assuming that season took place in 2017, it can be inferred that Jessi was born in 2004.
  • Jessi has nipple hairs, which are black despite her regular hair being red.
  • Jessi dressed up as Ruth Bader Ginsburg for Halloween in "Horrority House".
  • Jessi Glaser is named after her voice actor, Jessi Klein.
  • In "The Shane Lizard Rises" it is revealed that Jessi doesn't shave her legs as she claims women don't need to shave but after being bullied over it by Devin tries to shave but ends up badly cutting herself due to not knowing how to use a razor. It is unknown is Jessi will try to shave again.