Sebastiaan Matheus Sigismund de Ranitz (10 July 1833 – 25 February 1909) was a Dutch jurist and parliamentarian.

During his time in parliament, he served as the chairman of the Justice Committee (1887) and spoke about matters of crime, finance, and foreign affairs, as well as the revision of the Constitution of the Netherlands.

[1] Effective 1 January 1889, De Ranitz left his prosecutorial role to become a justice with the Amsterdam Court of Appeal.

On 10 May 1890, he was appointed to the Supreme Court of the Netherlands (also in The Hague) by King William III, taking office in June.

The De Ranitz family was granted a noble predicate, jonkheer, by royal decree on 16 August 1906.