The Marshall Gambit may refer to a number of chess openings named after the American chess master Frank Marshall. It is not to be confused with the Marshall Defense.
Common meanings 1.d4 d5 2.c4 e6 3.Nc3 c6 4.e4 dxe4 5.Nxe4 Bb4+ 6.Bd2 (a line reachable from the Queen's Gambit Declined or, less often, the Slav Defense) 1.e4 d5 2.exd5 Nf6 (a line of the Scandinavian Defense; it may also be called the Modern Scandinavian) 1.d4 d5 2.c4 e6 3.Nc3 c5 4.cxd5 exd5 5.e4 (a line of the Tarrasch Defense) 1.e4 e6 2.d4 d5 3.Nc3 c5 (a line of the French Defense) 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 Be7 6.Re1 b5 7.Bb3 0-0 8.c3 d5 (a line of the Ruy Lopez; more often called the Marshall Attack)