Yes, Mormons (members of The Church of Jesus Christ of Latter-day Saints) believe the Book of Revelation is a part of the Bible. They accept the King James Version of the Bible, which includes the Book of Revelation, as scripture "as far as it is translated correctly."
They also believe that the Book of Revelation is best understood in conjunction with other scriptures, including the Book of Mormon, Doctrine and Covenants, and Pearl of Great Price. These scriptures provide additional context and clarification, according to Mormon belief, that help to interpret the symbolism and meaning of Revelation.