John T. Walsh (February 15, 1816 – August 6, 1886) was a minister and Millerite who after the Great Disappointment, led a group of Adventist Millerites. They believed that Christ had returned on October 22, 1844, only invisibly, and that the Millennium had begun on that date. This group organized as the Life and Advent Union in 1863, which later became part of the Advent Christian Church.