Gregory "Greg" Siff (born December 21, 1977) is an American visual artist, designer, writer and actor who lives and works in Los Angeles.

[2] Siff has done commissions and installations for Deitch Projects,[3] The Standard Hotel,[4] Mercedes Benz,[5] Tumblr,[6] Christie's, Sotheby's,[7] Vans, Red Bull, The Art of Elysium,[8] Siren Studios, Wexlers Deli,[9] and Warner Bros. Records, among others.

[15][16] In Spring 2013, Siff was selected by Vans Custom Culture[17] to be one of their "Art Ambassadors", inspiring students across the United States to embrace their creativity.

In October 2013 Siff collaborated with Helmut Lang and Project Angel Food, a Los Angeles-based charity whose mission is to help those affected by HIV/AIDS, Cancer, Diabetes, and other life-threatening diseases.

[21][non-primary source needed][22] Also in April 2014, Siff exhibited in the Santa Monica Museum of Art's Precognito/Incognito 10 alongside work from Ed Ruscha, John Baldessari, Sage Vaughn and Oscar Murillo.

Other artists in the exhibition included Marina Abramovic, Patti Smith, Janet Cardiff, Brandon D'Leo, James Franco, Michael Stipe, Tom Sachs, and Adrián Villar Rojas.

[24] In 2017, Siff collaborated with luxury fashion house Saint Laurent, bringing his imagery to the new Winter YSL 2017 Women's and Men's Ready to Wear Line.

In 2008, Siff wrote and starred in, The Nothing Boys,[26] a semi-autobiographical play about a young man who returns home to his high school for his 10-year reunion only to find one other student in attendance.