The 2005 British Columbia general election was held on May 17, 2005, to elect members of the Legislative Assembly (MLAs) of the Province of British Columbia (BC), Canada. The British Columbia Liberal Party (BC Liberals) formed the government of the province prior to this general election under the leadership of Premier Gordon Campbell. The main opposition was the British Columbia New Democratic Party (BC NDP), whose electoral representation was reduced to two MLAs in the previous provincial election in 2001.

The BC Liberals retained power, with a reduced majority of 46 out of 79 seats, down from the record 77 out of 79 in 2001. While the popularity of Campbell's government was affected by various factors such as its resolution of the Fast ferry scandal inherited from the previous NDP government, the sale of BC Rail, and Campbell being convicted for driving under the influence in January 2003, the overwhelming majority they earned at the previous election held up well enough for them to remain comfortably in control of the Legislative Assembly. Voter turnout was 58.2 per cent.

Under amendments to the BC Constitution Act passed in 2001, BC elections are now held on fixed dates: the second Tuesday in May every four years. This was the first provincial election for which elector data in the provincial elector list was synchronised with the National Register of Electors.

Coincidental with the general election, BC voters also voted on whether or not to change the province's electoral system.

The BC electoral reform referendum was held in conjunction with this election. This referendum asked voters whether or not they support the proposed electoral reforms of the Citizens' Assembly on Electoral Reform, which included switching to a single transferable vote (STV) system. Had it been approved by 60% of voters in 60% of ridings), the new electoral system would have been implemented for the general election in 2009. Although the proposed reform attracted a clear majority (58% of the popular vote in favour, with 77 out of 79 ridings showing majority support), the level of support was just short of that required for mandatory implementation. A new vote on a revamped version of STV was held in conjunction with the 2009 British Columbia general election.

xx Denotes party received less than 0.1%

Besides the usual public polling by market research firms, other organizations have been attempting to predict the results of the upcoming election using alternate methods. Results suggest that all three projections below underestimated NDP seats and overestimated Liberal seats:

UBC's Election Stock Market tracks the prices of contracts whose value depend on election results: [1]
Popular vote: Lib 44.5%, NDP 35.9%, Green 13.9%, Other 5.3%
Seats: Lib 48.6 (61.5), NDP 29.4 (37.2), Other 1.6 (2.0)
(values in parentheses are values of actual contracts, in cents)