Louis Ruffet (13 April 1836, in Nyon – 1923) was a Swiss Protestant theologian and church historian.
In 1859 he received his bachelor's degree in theology at the École de theologie in Geneva and became ordained as a minister at the Église de l'Oratoire.
He served as a minister in the French communities of Royan, Le Creusot and Aix-les-Bains, and in 1861 returned to Geneva as a minister at the Église de l'Oratoire, where he preached until 1869.
In 1870–72 he worked as a director of a seminary in Lausanne, and afterwards, taught classes in church history at the École de théologie in Geneva.
In 1874 he was awarded an honorary doctorate in theology from Princeton University.