Luxembourg's three smaller parties reached a deal Monday on a coalition program, clearing the way for a new government to take office Wednesday, a move that would bring to an end Prime Minister Jean-Claude Juncker's almost 20 years in power.

The agreement came after elections in October that saw Mr. Juncker's centrist Christian Social People's party finish first. However, Xavier Bettel's center-right Democratic Party, the Socialists and the Greens collectively picked up 32 of the parliament's 60 seats, giving them a parliamentary majority.

The coalition accord must still be approved by the coalition parties, which is expected to happen Tuesday.

Mr. Bettel, a popular mayor of Luxembourg city, is set to be the new prime minister.

Mr. Juncker is expected to formally resign Wednesday morning and Luxembourg's Grand Duke Henri would then invite the three-party coalition to take office, according to Luxembourg officials.