Kimberly "Kim" Wexler is a fictional character in the television series Better Call Saul, a spin-off of Breaking Bad. Kim is primarily portrayed by Rhea Seehorn, and was created by Vince Gilligan and Peter Gould. An intelligent and proficient lawyer, she is the confidante and love interest of Jimmy McGill / Saul Goodman, whom she later marries. Kim's characterization and Seehorn's performance have received critical acclaim, earning her two Primetime Emmy Awards for Outstanding Supporting Actress in a Drama Series nominations.

In writing the pilot for Better Call Saul, showrunners Vince Gilligan and Peter Gould included the character of Kim but due to her being a new character to the Breaking Bad universe, especially in relation to Jimmy McGill / Saul Goodman or Mike Ehrmantraut, they had not yet developed a plan for her story. Gilligan said the writers had written Kim as "perhaps a love interest past tense, or potential love interest future tense", and possibly waning out of Jimmy's life later. She was originally a "tempering influence" for Jimmy, but otherwise the writers had few ideas as to where else they would take her character. Rhea Seehorn auditioned and got the role in April 2014, about two months before the pilot was shot. According to casting director Sharon Bialy, they had used two fake scenes to keep the high-profile project a secret, and when Seehorn auditioned and impressed them with both scenes, only then did they go to the next step and explain the audition's true purpose. Seehorn was able to adapt to this change to the role of Kim in a single take.

The pilot had two scenes with Kim, one which involves her counseling Jimmy after Howard Hamlin chews him out. The scene as written had minimal direction, but Seehorn, in preparing for the shot, saw a number of subtleties with the scene that suggested she knew Jimmy intimately, that she had boundaries, and she was used to cleaning up after Jimmy's mistakes. She also felt from this scene that Kim would prefer to listen before speaking and using that as a position of power. The writers saw how Seehorn acted out the scene and realized how much more it defined the character going forward, someone that prioritized work and placed boundaries on her relationship with Jimmy but still cared for him. Gilligan considered Seehorn's ongoing performance as Kim essential to her development. Seehorn had already gotten an idea that Kim enjoyed participating on Jimmy's cons, a fact established in the screenplay for the fourth episode of the first season "Hero", but which Seehorn had yet to see. Seehorn was able to use very subtle smiles to indicate Kim's appreciation for Jimmy during that episode, which Gould said, "The way she played it just felt so right that it gave us a strong feeling for where we were going with her." Gould later said of Wexler's acting, "Kim Wexler has the greatest poker face of any character I've ever seen. She's somebody who knows when to stay silent instead of speaking her mind, but while this character can conceal her thoughts from the other characters in the scene, we in the audience can see everything that's going on in her. It's a magic trick that is remarkable. It has a lot to do with Rhea's intelligence. She has such a sharp, perceptive way of looking at the world, and she brings that to Kim."

With this change, the writers saw Kim no longer being as moral as planned and gave her a darker side that arose from her childhood, something that gave her a chip on her shoulder that would make her give in to more unethical approaches if it got the job done, and thus one that readily fell into work alongside Jimmy in his cons after fighting her reluctant nature to join in. Gould called this "The emotional connection between these two characters had a gravitational pull that started twisting the whole story around." This also drastically altered the direction they took Jimmy's transformation into Saul. The first-season finale, "Marco" shows Jimmy walking away from a potential job with the law firm Davis & Main that Kim had set up for him. Season two was to continue with Jimmy outright forgoing the job, but because the writers wanted to include Kim more based on Seehorn's performance, they altered this to show Jimmy returning and accepting the job for Kim's sake.

During the first two seasons, Kim was rarely seen without a business suit or a tight ponytail, a choice made between Seehorn, Gilligan, Gould and stylist Trish Almeida to show that Kim was "all business". In the third season, Kim gets into a car accident, breaking her arm which in actuality would make it difficult for Kim to put up her hair in a ponytail without significant effort. At this point, as Kim's character was starting to become unravelled, Almeida and Seehorn used how tight the ponytail was set as an implicit sign of Kim's internal turmoil: when it was set tight, Kim was focused on her job, but if it was loose, it meant she was struggling with sadness and worry.

Gilligan has called Kim's arc through the fifth season an "impending tragedy", as her nearly illegal actions are towards "self-destructive behavior". Katie Beth Hall portrays a young Kim in a flashbacks in "Wexler v. Goodman" and "Axe and Grind".

According to her driver's license in "JMM", Kim was born in 1968. She was raised in several Nebraska towns, including Red Cloud, but is intentionally vague about her past. In a flashback in "Wexler v. Goodman", Kim is shown to have become self-reliant as a teenager due to her mother's alcoholism. In "The Guy for This", she claims that as a child, her mother frequently moved them from place to place to keep one step ahead of landlords to whom they owed back rent, and never had a place to call home herself. Kim further claims she moved to Albuquerque because of the limited opportunities available in her hometown. Kim's mother used her in shoplifting and petty theft schemes, such as stealing a necklace and earrings which Kim has kept through adulthood, as shown in "Axe and Grind".

Kim worked in the mailroom at Hamlin, Hamlin and McGill (HHM), where Howard Hamlin and Chuck McGill were lead partners. Chuck's younger brother Jimmy was employed in the mailroom because of Chuck's insistence that he work a legitimate job and rid himself of his con artist past. With HHM lending her the money to pay for law school, she completed her education and then joined the firm as an associate.