Below are the 2021 MLS officials, along with their home country.
Referees
United States
Fotis Bazakos
Allen Chapman
Alex Chilowicz
Marcos DeOliveira II
Joe Dickerson
Ismail Elfath
Tim Ford
Guido Gonzales Jr.
Alan Kelly
Jair Marrufo
Rosendo Mendoza
Chris Penso
Victor Rivas
Nima Saghafi
Robert Sibiga
Kevin Stott
Baldomero Toledo
Ramy Touchan
Ted Unkel
Rubiel Vazquez
Armando Villarreal
Canada
Drew Fischer
Dave Gantar
Silviu Petrescu
Assistant Referees
United States
Frank Anderson
Ian Anderson
Kyle Atkins
Claudiu Badea
Peter Balciunas
Andrew Bigelow
Cameron Blanchard
Gjovalin Bori
Eric Boria
Logan Brown
Jose Da Silva
Brian Dunn
Chris Elliott
Adam Garner
Jeffrey Greeson
Benjamin Hal-Volpenheim
Jeremy Hanson
Jeff Hosking
Jeremy Kieso
Kevin Klinger
Peter Manikowski
Apolinar Mariscal
Eduardo Mariscal
Felisha Mariscal
Ian McKay
CJ Morgante
Matthew Nelson
Kathryn Nesbitt
Corey Parker
Brian Poeschel
Cory Richardson
Corey Rockwell
Mike Rottersman
Nick Uranga
Eric Weisbrod
Jason White
Adam Wienckowski
TJ Zablocki
Canada
Micheal Barwegen
Philippe Briere
Gianni Facchini
Richard Gamache
Oscar Mitchell-Carvalho
Chris Wattam
Video Assistant Referees
United States
Malik Badawi
Jon Freemon
Hilario Grajeda
Jorge Gonzalez
Edvin Jurisevic
Alejandro Mariscal
Younes Marrakchi
Daniel Radford
Jose Rivero
Ricardo Salazar
Sorin Stoica
Kevin Terry Jr.
Canada
Geoff Gamble
Assistant Video Assistant Referees
United States
Jozef Batko
Jonathan Johnson
Mike Kampmeinert
Kyle Longville
Craig Lowry
Jeff Muschik
Joshua Patlak
Tom Supple
Fabio Tovar
Canada
Rene Parra
Rob Schaap
