In a landslide majority, the Liberal Party of Germany (FDP) approved the coalition agreement with the Social Democratic Party (SPD) and the Greens, at a party conference on Sunday.
This follows Saturday's SPD conference, which approved the so-called "traffic light coalition" set to install their candidate Olaf Scholz as chancellor next week, taking over from Angela Merkel.
The FDP delegates voted in favour of the coalition agreement with 92.4%.
The most important issues of the coalition agreement are a minimum wage of €12, the climate crisis, restructuring the economy, affordable living, and other improvements for low-income earners and families.
The coalition is expected to get the final "all clear" on Monday when the Greens publish the result of their member survey.
The FDP's party leader and soon-to-be Minister of Finance Christian Lindner lobbied hard within his party to accept the coalition.
"In the end, we now have a coalition agreement that I am convinced is not characterised by where we have limited each other. Rather, this coalition agreement is characterised by the fact that we have expanded and complemented each other," Linder said.
Once the three parties give their go-ahead, the new coalition will be completed on Tuesday.