Jehovah's Witnesses do not celebrate Christmas for several reasons. One reason is that they believe that Christmas has become too commercialized and has lost its true meaning. They also believe that Christmas is based on pagan traditions that are not in line with their religious beliefs. Additionally, they believe that the Bible teaches that Jesus was born in the fall, not in December. Therefore, they choose to celebrate the birth of Jesus at a different time of year, such as in the spring or summer.