Yes, UPS does work on Christmas Eve. In fact, UPS operates its largest delivery day of the year on Christmas Eve to ensure that packages get delivered on time. They also work closely with their customers to make sure they can receive their packages as quickly and efficiently as possible. UPS is committed to making sure everyone gets their gifts in time for Christmas Day, and their employees work hard to make it happen. So if you have a package you're expecting to arrive on Christmas Eve, rest assured that it's in good hands with UPS.