The 1907 ECAHA season was the second season of the Eastern Canada Amateur Hockey Association (ECAHA). Teams played a ten-game schedule. The Montreal Wanderers lost the Stanley Cup to the Kenora Thistles of the Manitoba Hockey Association mid-season, but went undefeated in the regular season to win the league championship. They proceeded to defeat Kenora in a two-game total goals series to win back the Cup.

Nationals and Grand Trunk applied for franchises but did not get three-fourths approval.

Frank McGee of Ottawa retired to pursue his government career. The Wanderers added two professionals, Riley Hern from the Portage Lake-Houghton pros and Hod Stuart from the Pittsburgh pros.

Prior to the season, Ottawa travelled to Winnipeg for a series of exhibition games against Manitoba league teams including the Kenora Thistles, who then came east to play a challenge in Montreal. The Montreal Victorias hosted the St. Nicholas Hockey Club from New York in an exhibition on December 22, 1906, defeating them 16–3.

A major battle took place for the game between the Senators and Wanderers on January 12. Stick work was the order of the day as Charles Spittal of Ottawa knocked Cecil Blachford in the head, Alf Smith hit Hod Stuart in the head and Harry Smith broke Ernie Johnson's nose. The Wanderers would still win, 4–2.

After the game, a special league meeting was called to hand out discipline, with Victorias and Wanderers wanting Spittal and Alf Smith suspended for the season. The players were not suspended, leading the league president Mr. McRobie to resign, leaving Darcy McGee to take over as president.

On the next visit of the Ottawa team to Montreal, to play the Victorias, the three Ottawa players were arrested by Montreal police. Eventually Alf Smith and Spittal were fined $20 for their actions and Harry Smith was found not guilty.

The scoring championship was close, with Ernie Russell of the Wanderers placing first with 42 goals in 9 games, and Russell Bowie scoring 38 in 10 games.