Jane Frances Kaczmarek (born December 21, 1955) is an American actress. She is best known for playing the character of Lois on the television series Malcolm in the Middle. She lives in San Marino, California.

Kaczmarek, a Polish American, was born in Greendale, Wisconsin, the daughter of Evelyn, a teacher, and Edward Kaczmarek, a defense department worker. She majored in theater at the University of Wisconsin–Madison. She later studied at the Yale School of Drama for her graduate degree and was a part of its theater company. She has had several Broadway hits, including Lost In Yonkers and Raised In Captivity, where she won an LA Drama Critics’ Award. Her first television role was that of Margie Spoletto on For Lovers Only (1982). Her first major role was that of Linda Bauer on Equal Justice from 1990-1991.

Kaczmarek has also appeared in over forty television roles, the most notable including: