For example Rabbi Neustadt writes in his book
““it depends on the type of party the company is having. Many times, a company’s holiday party has nothing to do with the celebration of the holiday.” It may instead be an “employee appreciation party,” which happens to be held during the non-Jewish holiday season; in that case, “there is no halachic objection to attending. But if the intention of the party is to celebrate the actual non-Jewish holiday, it would be forbidden for a Jew to attend.”
what the party is called very mush matters. Though it might not necessarily be muttar even if it isnt a party celebrating a specific goyish holiday