L. Timmel Duchamp was born in 1950, the first child of three, to very young parents. Family friends and relatives lavished nicknames on her at home, and at school, her peers (two of whom shared her first name) bestowed a series of nicknames on her as well. Sad to say, her first name never suited her personality and just about everyone knew it. Which is why, when she went away to college, she asked everyone she met to call her "Timmi."
She discovered feminism in the early 1970s when she read Kate Millett's Sexual Politics. But she had always been a protofeminist, likely because her mother and paternal grandmother were powerful personalities who exercised considerable personal agency. And she discovered science fiction a couple of years later, when she picked up Samuel R. Delany's The Einstein Intersection off a display table in the bookstore in the Student Union.
Duchamp first began writing fiction in a library carrel at the University of Illinois in 1979, for a joke. But the joke took on a life of its own and soon turned into a satirical roman a clef in the form of a murder mystery (complete with chapter epigraphs from Lacan, Freud, and Norman O. Brown, a heroine named Gretta Cobb-Ozouf, and a sexy detective love-interest named Jason Thunder) titled "The Reality Principle." When she finished it, she allowed the novel to circulate via photocopies, and it was a great hit in the academic circles in which she then moved. She so enjoyed writing fiction that she decided to try her hand at writing a literary novel suffused with magic realism. By the time her manuscript had reached 950 pages, though, she realized that it lacked a narrative shape and would simply go on and on and on if she continued working on it. Obviously she needed to learn about narrative construction, so she spent the next year or so trying to figure it out. She was still working on it when one night in the fall of 1984 she sat down at her mammoth Sanyo computer with its green phosphorescent screen and began writing Alanya to Alanya.
Duchamp spent the next two years in a fever, writing the Marq'ssan Cycle. When she finshed it, she realized she didn't know how to market it to publishers and decided that publishing some short fiction (which she had never tried to write before) would be helpful for getting her novels taken seriously. Her first effort at a short story was "Welcome, Kid, to the Real World," which she wrote in the summer of 1986. Her next effort, however, turned into a novel. (Getting the hang of the shorter narrative form was a lot harder than she'd anticipated.) So she decided to stick with novels for a while. When in fall 1987 a part-time job disrupted her novel-writing, she took the short stories of Isak Dinesen for her model, tried again, and wrote "Negative Event at Wardell Station, Planet Arriga" and "O's Story." And in 1989 she sold "O's Story" to Susanna J. Sturgis for Memories and Visions, "The Forbidden Words of Margaret A." to Kristine Kathryn Rusch for Pulphouse: The Hardback Magazine, and "Transcendence" to the shortlived Starshore. Her first pro sale, though, was "Motherhood, Etc." to Bantam for the Full Spectrumanthology series.
After that she wrote a lot of short fiction (mostly at novelette and novella lengths), a good deal of which she sold to Asimov's SF. In the late 1990s Nicola Griffith convinced her to try her hand at writing criticism and reviews. In 2004, Duchamp founded Aqueduct Press; since then editing and publishing books (her own as well as other writers')has claimed the lion's share of her time and effort.
She lives in Seattle.