The Walker Trustees administer a bequest made for the advancement of the Scottish Episcopal Church. The trust was founded by the Walker Trust Act 1877, a private act of the United Kingdom Parliament, to administer a bequest made by sisters Barbara and Mary Walker. The Walkers left an estate valued at £178,586 12s (equivalent to £21,235,022 in 2023) to be used to construct a new place of worship, which became St Mary's Cathedral, and to provide for other needs of the church. Because the cost of the cathedral was in excess of that described by the Walkers in their bequest disposition the act of parliament was required to permit the administrators to mortgage the part of the estate to cover construction costs. The act appointed the Episcopal Bishop of Edinburgh, the Episcopal Dean of Edinburgh, the Lord Provost of Edinburgh, the Deputy Keeper of Her Majesty's Signet for Scotland and the Treasurer of the Bank of Scotland and their successors in those offices as trustees.
The act was replaced in its role of governing the bequest by a 2019 declaration of trust and the trustees now comprise the bishop, dean, diocesan secretary and two others. It continues to provide funds for the church. As part of Mary Walker's bequest the trustees became vested with the hereditary office of Gentleman Usher of the White Rod, a historic office of the Parliament of Scotland. This originally granted an income from fees on honours granted to Scottish people but this ceased in 1911. The trustees have successfully petitioned that a representative play a role at coronations of British monarchs and the current bishop, John Armes, participated in the 2023 coronation of Charles III and Camilla.