Illilouette Fall, Waterfall in Yosemite National Park, United States.

Illilouette Fall is a 381-foot (116 m) waterfall on Illilouette Creek, a tributary of the Merced River in Yosemite National Park. It drops in a small canyon cut into the south wall of Yosemite Valley, directly across from Vernal Fall. The narrow canyon below is craggy and filled with rapids during the wet season.

Lafayette Bunnell recorded the Ahwahneechee name of the fall as "Too-lool-lo-we-ak" and suggested its literal translation was unfit for everyday use; that translation is now lost. The name "Illilouette" may be a perversion of that Ahwahneechee name, though this is not certain. The origin and meaning of "Illilouette" itself remain unknown.

The name Illilouette has no known meaning; Lafayette Bunnell recorded the Ahwahneechee name as "Too-lool-lo-we-ak" and suggested its literal translation was unfit for everyday use, though that translation is now lost. The modern name may be a perversion of that Ahwahneechee word, but this is uncertain.

The fall is best seen from the Panorama Trail as it descends from Glacier Point. From the Mist Trail and John Muir Trail near Vernal Fall it faces south but can vanish entirely in low-flow months. No trail reaches the base: the narrow canyon is craggy and filled with rapids in the wet season, though low water allows an unencouraged descent.

Lafayette Bunnell recorded the Ahwahneechee name of the fall as "Too-lool-lo-we-ak" and suggested its literal translation was unfit for everyday use; that meaning is now lost. "Illilouette" may be a perversion of that name, though this is uncertain.