De Marchi or DeMarchi is a surname. Notable people with the surname include:
Alberto de Marchi (born 1986), Italian rugby union player
Alessandro De Marchi (conductor), Italian conductor
Alessandro De Marchi (cyclist) (born 1986), Italian cyclist
Denny DeMarchi, Canadian musician
Emilio De Marchi (1861–1917), Italian opera singer
Juan De Marchi (1866–?), Italian anarchist
Laura De Marchi (born 1936), Italian actress
Marco De Marchi (born 1966), Italian footballer and agent
Matthew de Marchi (born 1981), American-born Italian ice hockey player
Neil De Marchi, Australian economist
Secondo De Marchi (born 1911), Italian boxer
Steve DeMarchi, Canadian musician
Suze DeMarchi (born 1964), Australian singer-songwriter
