Slavko J. Grujić (; 15 February 1871 – 24 March 1937) was a Serbian diplomat, marshal of the court, and philanthropist. A skilled diplomat he was one of the main contributors of the response to the Austrian ultimatum of 23 July 1914, which some scholars have called "a masterpiece of diplomatic equivocation”. After the First World War, he became Yugoslavia's first ambassador to the United States returning to serve as Marshal of the Court to King Peter II of Yugoslavia. He died in London, while serving as ambassador of Yugoslavia to the United Kingdom, in 1937.