Julian Randolph Stow's paternal grandfather was Francis Leslie Stow, a Crown Solicitor of Western Australia. Stow's great-grandfather was Randolph Isham Stow, a judge on the Supreme Court of South Australia and Attorney General of South Australia; a great-great-uncle, Jefferson Stow was prominent as an explorer of northern Australia, and Stow's great-great-grandfather, the Rev. Thomas Quinton Stow, was a pioneering Congregational minister in South Australia. The Stow family was from Suffolk, where they had owned land for several generations before Thomas Stow was appointed the colonial missionary to South Australia by the London Colonial Missionary Society in 1836. In 1837, they relocated to South Australia. After Thomas Stow's death, the Stow Memorial Church was constructed in his honor. His wife, Elizabeth Randolph Eppes, was American and her mother was Thomas Jefferson's first cousin. The Stow lineage can be traced back to the Plantagenets and William the Conqueror.