The South American side beat the Netherlands in the semi final last night, winning 4-2 on penalties after the game finished nil-all after extra time.
Maxi Rodriguez scored the decisive penalty for Argentina after goalkeeper Sergio Romero had saved penalties from Ron Vlaar and Wesley Sneijder in the shoot-out.
Netherlands boss Louis van Gaal says it was a struggle to find willing penalty takers, with two players refusing to go first.
Vlaar volunteered in the end, but had his spot kick saved, which set the tone for the shootout as a whole.
It'll be the third time Germany and Argentina have faced off the in World Cup final.
They played each other in both the 1986 and 1990 finals, with each team winning once.
The Netherlands will have to settle for a 3rd/4th place play-off against tournament hosts Brazil on Saturday.