Dmitry Vladimirovich Gaag (??????? ???????????? ????; born March 20, 1971 in Qaragandi) is an athlete from Kazakhstan, who competes in triathlon.
Gaag competed at the first Olympic triathlon at the 2000 Summer Olympics.
He took fourth place with a total time of 1:49:03.57.
He competed again at the second Olympic triathlon at the 2004 Summer Olympics, dropping to twenty-fifth place with a time 1:56:28.97.
On September 6, 2008 Gaag was banned for two years beginning June 20, 2008 after testing positive for recombinant erythropoietin (EPO).