The kangaroo was seen by zoo employees and visitors Wednesday morning, and is thought to have been taken sometime during the day.
Zoo Director Matthias Schmitt said Mila is still very young and would be unlikely to wander far from her mother on her own. He said search dogs were brought and did not detect any traces of foxes or other predators that could have invaded the enclosure and taken the young marsupial.
"We have to assume that Mila was stolen," Schmitt said.
The zoo is asking anyone with information on Mila's whereabouts to contact police.