They're not. Until recently the Speaker was a Democrat called Nancy Pelosi. It depends on which party controls the House.
The most recent Republican Speaker of the House was Dennis Hastert of Illinois.
Majority party
The Speaker of the House. When the democrats were in the majority, Nancy Pelosi was Speaker. The House is currently under republican control and John Boehner occupies the Speakers chair.
The House of Representatives is lead by the Speaker of the House.
As of July 2014, John Boehner is the Speaker of the United States House of Representatives. He is a member of the Republican Party.
The speaker of the house is John Boehner (Bay-Ner) who is a republican.
Republican
The leader of the US House of Representatives is called the Speaker of the House. As of January 2011, the Speaker is Republican John Boehner of Ohio. The Speaker is elected by the members of the House and historically will be chosen from the majority party in the House. The equivalent position for the opposition party is the Minority Leader.
As of 2010, the Speaker of the House is Nancy Pelosi.
For the 112th Congress (2011-2012), the Speaker of the US House is John Boehner, a Republican representative from Ohio.
Speaker of the House for the 2008 season of the Virginia General Assembly is William Howell, Republican from the 28th District (Stafford).
As of January 4th, 2011, the 61st Speaker of the House of Representatives is John Boehner(Republican from the 8th district of Ohio).