Thomas S. "Tom" Christiansen[1] (born February 13, 1963), nicknamed tchrist or occasionally thoth, is a Unix developer and user known for his work with the Perl programming language.

Christiansen worked for several years at TSR Hobbies before attending the University of Wisconsin - Madison where he earned B.A.

[2] In 1993, he established the Tom Christiansen Perl Consultancy, located in Lake Geneva, Wisconsin.

[1] In 2010, he joined the Biomedical Text Mining Group at the University of Colorado School of Medicine.

[4] He was the author of much of the core Perl documentation, including the manual pages perlfaq and perltoot, development of perl.com.