George Washington McGinnis (c. 1850s – May 18, 1934) was an American pitcher whose Major League Baseball career spanned from 1882 to 1887.

Nicknamed "Jumbo" for his heavy, robust frame, McGinnis is considered the first ace of the storied franchise that would later become known as the St. Louis Cardinals.

McGinnis's actual birthdate is unknown and has been the subject of some debate and speculation by baseball historians.

Records are inconsistent, and different sources list it as February 22, 1854,[citation needed] sometime in 1856, 1858 (according to his gravestone), or as late as February 22, 1864 (found on his death certificate)[1]— although the latter date is unlikely, since it would mean that he made his pitching debut in the American Association at the age of 18.

After the team acquired Bob Caruthers and Dave Foutz, however, McGinnis' role on the Browns' pitching staff was greatly reduced.