In what year did the NHL expand from the Original Six to 12 teams? The answer is 1967.
The 1967 NHL expansion added six franchises for the 1967–68 season, doubling the league from six teams to 12 and ending the Original Six era. The new clubs were the Los Angeles Kings, Minnesota North Stars, Oakland Seals, Philadelphia Flyers, Pittsburgh Penguins, and St. Louis Blues.
The expansion was driven by pressure to establish a stronger national presence, concerns about rival leagues, and hopes of securing more valuable television opportunities in the United States. All six expansion teams were initially placed in a new West Division, while the Original Six formed the East Division.
The expansion also changed the league’s competitive landscape. The Philadelphia Flyers became the first of the new franchises to win the Stanley Cup, taking championships in 1974 and 1975. The Minnesota North Stars later relocated and became the Dallas Stars.