Signal du Mont du Chat, Mountain summit in Savoie, France.

Signal du Mont du Chat is a limestone summit in the Jura Mountains, in the Savoie department of eastern France, rising to 1,504 meters. It sits above Lake Bourget and offers a wide view over the Alps, including Mont Blanc. A telecommunications tower with a red-and-white cylindrical mast and a lattice base stands on the hilltop.

The climb of the Mont du Chat has appeared in the Tour de France only twice, in 1974 and 2017. In 2017 it was rated hors catégorie over 8.7 km at 10.3%; Warren Barguil crossed first, and Richie Porte crashed on the descent, breaking his clavicle and pelvis. A month earlier Fabio Aru led over the top in the Critérium du Dauphiné.

The name Mont du Chat is recorded from 1209, when a charter mentions "A supercilio montis Catti". Legends attributed it to a shaggy cat that frightened travellers, while Adolphe Gros linked it to the personal name Catus or Cattus. The summit carries a telecommunications tower, and the D42 road was opened in 1965 when the ORTF transmitter was installed.

The road up is paved and clearly signed, but several tight hairpin bends make the ascent demanding for both drivers and cyclists. The best time to visit is from spring to fall, when snow and ice are unlikely to be a concern.

The summit carries a red-and-white banded telecommunications tower, built after the ORTF transmitter was installed here; the D42 road was opened in 1965 to serve it. A low flat-roofed building with dish antennas stands beside the lattice base.