The Comfort Women Peace Monument honors Korean woman who were forced into being sex slaves for the Japanese military during World War II.
Investigators say the statue's face was smeared and several flower pots around the memorial were shattered.
Police believe the vandals struck early Thursday morning.
Outraged members of both the Korean and Japanese communities stood by the memorial Saturday to condemn the vandalism.
"We were extremely saddened and extremely shocked to learn that this has happened. The message is that this is not acceptable and that we want to make sure that this does not happen again," said Phyllis Kim with the Korean American Forum.
The statue has had somewhat of a controversial past.
Back in 2013, the year the memorial was installed, opponents filed a lawsuit to have it removed but it was unsuccessful.
"The kind of criminal act that was perpetrated on this statue is a strike against the symbol that this memorial represents," said former Congressman Mike Honda.
Authorities are not sure who vandalized it but anyone with information is asked to contact the Glendale Police Department.