The Missionary Society of the Methodist Episcopal Church v. Kelly was a case heard by the United States Supreme Court in 1883. The case involved a dispute between the Missionary Society and the Reverend William Kelly, a minister of the Methodist Episcopal Church. The Missionary Society had brought suit against Kelly for failing to pay a debt of $1,000 that he had incurred while serving as a missionary in the Society's employ. The Supreme Court held that the Missionary Society was entitled to recover the debt from Kelly. The Court reasoned that the Society had a right to enforce the contract between it and Kelly, and that Kelly was bound by the terms of the contract. The Court also held that the Society was entitled to recover the debt even though Kelly had been removed from the ministry of the Methodist Episcopal Church. The Court's decision in this case established that the Missionary Society had the right to enforce its contracts with its employees, even if those employees had been removed from the ministry of the Church. This decision was important in establishing the rights of religious organizations to enforce their contracts with their employees.

In Missionary Society of the Methodist Episcopal Church v. Kelly, the Supreme Court was asked to decide whether a trust created by an individual for religious purposes could be enforced against his estate after he passed away. The majority opinion held that such trusts were not enforceable because they violated public policy and interfered with testamentary freedom. However, in dissent Justice Miller argued that there was no reason why these trusts should not be recognized as valid under state law since they did not interfere with any important public policy or legal principle. He further noted that if individuals had the right to create charitable trusts during their lifetime, then it would follow logically that they should also have the right to do so through their wills after death. Therefore, he concluded that this trust should be upheld and enforced according to its terms.