Pat Mastelotto (born Lee Patrick Mastelotto, 10 September 1955, Chico, California) is a rock drummer who has worked with Mr. Mister, King Crimson and XTC, among others. For King Crimson he initially formed part of the "double trio", joining Bill Bruford on drums.

Mastelotto started playing the drums at the age of 10. When he was 16, he was playing in the most popular local bands and, while still in High School, commuted several hours to Lake Tahoe for gigs. Beginning in the 1970s, Mastelotto worked for many bands and as a studio session drummer, most notably for Mr. Mister, Scandal, Al Jarreau, Pointer Sisters, Patti LaBelle, Kenny Loggins, XTC, The Sugarcubes, Hall & Oates, Cock Robin, The Rembrandts, Jude Cole, Eddie Money, Tina Arena, Martika, Jack Wagner, the Suger Plastics, Danny Wilde, Mark Jordon, Mathew Sweet, Julia Fordham, Robyn Hitchcock, and David Sylvian.

In 1991, Mastelotto co-produced Peter Kingsbery's first solo album. Since 1994 Mastelotto has been a member of King Crimson, and appears on over 20 King Crimson CDs and several KC videos. He also produced, edit and mixed on several King Crimson ProjeKcts releases. He has also continued guesting on other projects (including recently Jay Terrien's solo debut album All the Dolls in the Same Place and the fourth Cock Robin album, released in 2006), work with the Swedish I/B/ band, a duet with drummer Terry Bozzio, CGT, Mecca, PJ Olsson, Tony Levin solo CD 'Stick Man' ( released in 2007 ) and with solo work. He is also a member of the progressive/experimental bands TU and KTU, with fellow King Crimson alumnus Trey Gunn, Tuner and Centrozoon, both with Markus Reuter, as well as his personal project, Mastica. In the 1990's Pat moved to Austin, Tx, and has worked with some of Austin's finest, including Storyville, Patty Grifith, Abra Moore, And the will now us by the Trail of the Dead, Will Taylor and Malford Milligan.
Pat Mastelotto at One World Theatre, 19 January 2003, with Terry Bozzio for a drum clinic
Pat Mastelotto at One World Theatre, 19 January 2003, with Terry Bozzio for a drum clinic

His playing style is flexible, with a long history of mixing traditional acoustic drums with various banks of electronic gear. He is equally comfortable with simple pop grooves as he is with the ornate, dense arrangements of playing in bands like King Crimson