Michael Welch is an American actor. He is perhaps best known for his roles as Luke Girardi on the TV series Joan of Arcadia and as Mike Newton in the 2008 film Twilight.

Welch was born in Los Angeles, California, and began his acting career at the age of ten. He is close friends with his Joan of Arcadia co-star Aaron Himelstein, who played the recurring character Friedman on the series. He and Himelstein had known each other for several years but did not become good friends until the series began in 2003.

Welch appeared in the 1998 film Star Trek: Insurrection, as well as on the television series Malcolm in the Middle, The X-Files, 7th Heaven, Cold Case, Without a Trace, NCIS, Crossing Jordan, The Riches, and Birds of Prey. He also narrated the Carl Hiaasen book, Flush, for CD in 2006. One of his most acclaimed roles is as a teenage version of Colonel Jack O'Neill (Young Jack O'Neill) in the Stargate SG-1 episode "Fragile Balance".

In 2008, Welch played Mike Newton in the film Twilight, based on the book by Stephenie Meyer. He is reprising the role in the film's 2009 sequel, New Moon.