"Donald Trump is the next president of the United States. We must immediately stand up against his xenophobic, Islamophobic, misogynistic, racist and sexist behavior," organizers said.
Demonstrators plan to gather at the historic Brandenburg Gate not far from the German parliamentary building Reichstag at 4:00 p.m. (13:00 GMT).
The "call to arms" was made on Facebook. Two thousands confirmed they were going and another 6,000 expressed their interest at the time of writing.
The message on Facebook said this was a registered protest, although Berlin police told local media they had not been officially notified as of Friday afternoon.
Protests across the United States have been going on since Wednesday when Republican nominee Trump beat his Democratic rival, Hillary Clinton, to US presidency. Dozens were arrested overnight in Portland, Oregon after demonstrations turned violent.