Gustav Felix Flatow - (January 7, 1875 – January 29, 1945) was a German gymnast. He competed at the 1896 Summer Olympics in Athens and at the 1900 Summer Olympics in Paris.
Flatow was Jewish, and was born in Berent, West Prussia, and in 1892 moved to Berlin.
Flatow competed in the parallel bars, horizontal bar, vault, pommel horse, and rings individual events. He won no medals, unlike his cousin and teammate Alfred Flatow. However, both were members of the German team that competed in the two team events, for parallel bars and the horizontal bar. As Germany won both those events (the horizontal bar unchallenged), Gustav earned two gold medals. He also competed at the 1900 Summer Olympics in Paris, but without winning medals. He retired from gymnastics to manage his textile company, which he founded in 1899.