Jean-Marc Troussier, aka Marco Troussier, born in 1956, is a French climber, mountaineer, ENSA mountain guide, and author.

Marco Troussier has had a distinguished career in French climbing and mountaineering. He has distinguished himself by opening numerous routes in prestigious massifs such as Mont Blanc, the Écrins, and the Verdon Gorges. A visionary, he actively participated in the development of free climbing in France, particularly in the 1980s, and contributed to the democratization of onsight climbing and "perpetual travel" on the world's cliffs. He was also involved in organizing the first climbing competitions in France, notably at Troubat. His name is associated with several routes, such as the southeast spur of the Aiguille des Ciseaux, known as the "Troussier route." Furthermore, he participated in the exploration and opening of the first icefalls in the Alps in the early 1980s, particularly in the Briançon region, with his brother Stéphane Troussier. He has been a professor at the National School of Skiing and Mountaineering (ENSA) in Chamonix, where he has trained numerous mountain professionals. As an author, he has published educational works and stories on climbing and mountaineering, as well as fiction, receiving the Prix du Pays du Mont-Blanc in 2013 and the Prix Littéraire des Écrins René Desmaison in 2014 for his novel Le Vent des Errances.

His career is recognized for his commitment to innovation, transmission, and mountain ethics.