Mike "Twin" Sullivan (September 23, 1878 – October 31, 1937) was an American boxer credited with taking the Welterweight Championship of the World on April 23, 1907, when he soundly defeated William "Honey" Mellody in Los Angeles in a twenty-round bout.

[1][2][3] Sullivan had three historic bouts with Hall of Famer and reigning lightweight champion Joe Gans, in September 1905 and January and March 1906 with the first in Maryland and the last two in San Francisco and Los Angeles.

In the San Francisco fight, Sullivan's first sanctioned Welterweight World Title match according to BoxRec, Gans won by knockout in the fifteenth of twenty rounds.

In an important note, the Rock Island Argus wrote of the San Francisco fight, "Gans showed wonderful form and was easily the master of his white antagonist at all times."

Lewis would use this victory and his subsequent knockout of Honey Mellody one year later on April 20, 1908, to establish what most boxing historians consider a legitimate claim to the World Welterweight Title.

[1] Sullivan met Honey Mellody, probably in his most historic bout, on April 23, 1907, in a Welterweight World Title match in Naud Junction Pavilion in Los Angeles.

Mellody's tactics were confined to rushes generally ending in clinches where Sullivan used right upper cuts and short hand jabs to the face with telling effect".

Sullivan fought Gardner again on November 29, 1909, at the Grand Opera House in New Haven, Connecticut, in a 12-round draw by newspaper decision of the Boston Globe.

[1] Sullivan fought Jimmy Clabby on February 4, 1910, at the National Athletic Club in Milwaukee, Wisconsin in a ten round draw by newspaper decision.