Courmayeur (French: [kuʁmajœʁ] ^ⓘ, Italian: [kurmaˈjør, -ˈjɛr]; Valdôtain: Croméyeui)^{[needs IPA]} is a town and comune in northern Italy, in the autonomous region of Aosta Valley, serving as one of the two bases on either side of Mont Blanc, Europe's highest mountain.

The toponym Courmayeur has been mentioned as Curia majori (1233–1381), Corte Maggiore (1620), Cormoyeu (1648), Cormaior (1680), Cormaior (Vissher, 1695), Cormaggior (L'Isle, 1707), Cormaior (Stagnoni, 1772) and Cormaieur (Martinel, 1799). The present toponym was first confirmed by Édouard Aubert (La Vallée d'Aoste, 1860), Joseph-Marie Henry (Histoire populaire de la Vallée d'Aoste, 1929) and Amé Gorret (Guide de la Vallée d'Aoste, 1877).

It became a popular tourist destination when alpinism arose, thanks to its proximity to Mont Blanc.

Under the Fascist regime and its "Italianist" rule, the town was briefly renamed Cormaiore. Courmayeur was reestablished in 1948 alongside all other French toponyms in the Aosta Valley.

The Mont Blanc Tunnel, connecting Courmayeur with Chamonix, opened in 1965, and provides an important road link between Italy and France. Courmayeur serves as one of the entry/exit points of the connecting tunnel and the tunnel forms part of the access between Italy and France, passing underneath Mont Blanc.

In 2013, in accordance with regional law 61 (Dénomination officielle des communes de la Vallée d'Aoste et protection de la toponymie locale), a referendum was carried out to change the official name to Courmayeur-Mont-Blanc, but there was insufficient support.

At an elevation of 1,224 m (4,016 ft) above sea level, it is located at the foot of the southern side of Mont Blanc, at 4,810 m (15,781 ft) the highest point in the Alps and western Europe (see Seven Summits), and is crossed by the Dora Baltea (fr. Doire baltée) river.

Courmayeur shares administration of Mont Blanc with its neighboring municipality of Saint-Gervais-les-Bains in France, and is consequently able to claim the title of highest commune in Italy.