The Bayern Munich star receives the Yashin Award from world soccer's governing body Fifa.
The 33-year-old, who also captains Germany, conceded just one goal in six matches as he led his team to the final.
Ireland's Robbie Keane was the only player to beat Kahn, with a last-minute equaliser in their group E match on 5 June.
He produced a string of stunning saves to help secure narrow 1-0 wins in the knock-out stages over Paraguay, the USA and South Korea.
He is the world's best keeper - there is no doubt about that
Germany coach Rudi Voeller
Kahn is a cult figure back in Germany, where newspapers have been producing cut-out-and-keep masks as a tribute to their idol.
Germany coach Rudi Voeller believes his goalkeeper is just as inspirational as more glamorous superstar out-field players like Ronaldo and Zinedine Zidane.
"He is the world's best keeper. There is no doubt about that," Voeller said.
"He has not only shown that in this World Cup, but also when winning trophies like the Champions League with Bayern Munich."
The World Cup has been a personal triumph for Kahn as he has rehabilitated his image following the humiliation of conceding five goals to England last September.
Kahn succeeds Frenchman Fabien Barthez, who was judged best goalkeeper at the World Cup in his home country four years ago when France were world champions.
Belgium's Michel Preud'homme won the first award in 1994.
The award is named in honour of Lev Yashin, the late Soviet goalkeeper who starred at World Cups between 1958 and 1966.