Lee Patrick Mastelotto (born September 10, 1955) is an American rock drummer and record producer. He has been a member of King Crimson, Stick Men, Mr. Mister and O.R.k., as well as working as a session drummer with XTC, The Pointer Sisters and The Rembrandts (including well known Friends theme song I'll Be There for You), among others. In addition, he has led or co-led other projects including Mastica, Tuner, TU and The Mastelottos.

For King Crimson, he initially formed part of the "Double Trio" lineup from 1994 to 1997, working with Bill Bruford as part of a double-drumkit arrangement. Following Bruford's departure in 1997, Mastelotto remained with King Crimson, becoming their longest-serving drummer and working both solo and in various configurations with subsequent drummers Gavin Harrison, Bill Rieflin and Jeremy Stacey.

Mastelotto is a pioneer and continuing developer of a mixed acoustic-and-electronic drumming approach which he refers to as "traps and buttons", and which incorporates techniques and methods from rock, pop and electronic dance music styles. As well as being a drummer, he works as a producer, engineer and mixer, working extensively with digital audio workstations.