De Marchi or DeMarchi is a surname. Notable people with the surname include:
Alberto de Marchi (born 1986), Italian rugby union playerAlessandro De Marchi (conductor), Italian conductorAlessandro De Marchi (cyclist) (born 1986), Italian cyclistDenny DeMarchi, Canadian musicianEmilio De Marchi (1861–1917), Italian opera singerJuan De Marchi (1866–?), Italian anarchistLaura De Marchi (born 1936), Italian actressMarco De Marchi (born 1966), Italian footballer and agentMatthew de Marchi (born 1981), American-born Italian ice hockey playerNeil De Marchi, Australian economistSecondo De Marchi (born 1911), Italian boxerSteve DeMarchi, Canadian musicianSuze DeMarchi (born 1964), Australian singer-songwriter