Members of The Church of Jesus Christ of Latter-day Saints often refer to Jesus Christ as their elder brother. This expression of endearment appears in sermons, lessons, and publications. In current usage, the term elder brother reflects an understanding that Jesus was the firstborn of the Father's spirit children and, since we humans are all spirit children of the Father, Jesus is our elder spirit brother. But that meaning was slow in coming to be articulated by Church leaders. The title is used enough that some might think that elder brother is one of the many titles attributed to Christ in the scriptures, but nowhere do the scriptures use this expression in reference to Jesus. Nor can the idea that Jesus is our elder brother be ascribed with certitude to the teachings of the Prophet Joseph Smith, although nothing he taught would seem to contradict the idea. The use of the title elder brother seems to make its first appearance the year of the Prophet's death (1844) in the writings of other Church leaders and soon thereafter greatly increased in usage and popularity. It is possible that Joseph Smith himself spoke this phrase toward the end of his life, for some reminiscences support that position. This article examines the usage in LDS discourse of the idea that Jesus Christ is the elder spirit brother of humankind, from its first documented occurrences. Then it reviews the logical and scriptural arguments that have been used to support the concept of Jesus as elder brother over the years, along with other possible interpretations of the truths upon which it is based.