Who choose the president in the event of a tie or if no candidate receives a majority of the electoral college vote?

In the event of a tie or if no candidate receives a majority of the Electoral College vote, the House of Representatives is responsible for choosing the president. Each state delegation in the House casts one vote for one of the top three candidates. This process is outlined in the 12th Amendment of the U.S. Constitution. If the House cannot decide on a president by Inauguration Day, the vice president-elect would serve as acting president until a decision is made.