Lois is a fictional character from Malcolm in the Middle. She is played by Jane Kaczmarek.
Lois is described as a hard-nosed, manipulative and slightly crazy mother and something of an embarrassment to her five kids and devoted husband, Hal.
Jane Kaczmarek herself describes Lois as 'a great mother'.
Lois is intensely disliked by Hal's wealthy and snobby family, as seen in the fourth-season episode "Family Reunion". They consider her low-class, and have taken to referring to her as "Lois Common Denominator".
She, in turn, took a strong and immediate dislike to Francis' wife Piama. Both of them take every opportunity to back-bite each other, but by the end of the series they have developed a much more cordial relationship.
In addition to being a full-time mom, Lois works at 'Lucky Aide', a local drugstore (motto: "The L stands for Value " ). Craig, one of her co-workers, clearly has a crush on her, which she does nothing to encourage. He often makes inept attempts to impress her.
Lois is believed to be descended from Poland or Eastern Europeans. This is implied by her love of Polish baseball players and her mother Ida's culture. Lois and Hal continue to be sexually attracted to one another and seem eager to expand their brood. In the series finale it is hinted that she is pregnant once again, but it is revealed that this is only a prank by Dewey. Her original plan was to have all girls.
In one episode, she gave her dying sister Susan ( Roseanne 's Laurie Metcalf) a kidney.
