Tyndall Glacier, Valley glacier in Yakutat City and Borough, Alaska, United States.

Tyndall Glacier is a 22 km long valley glacier in Wrangell-St. Elias National Park, about 110 km northwest of Yakutat. It originates at 2,400 m on the southwest flank of Mount Saint Elias and flows south-southwest to Taan Fjord, which opens into Icy Bay. The glacier is on average 1.6 km wide.

The glacier filled Taan Fjord until 1961. Over the following decades it retreated 17 km and thinned by 400 m. In 1991 the retreat paused at a shallow rock narrowing at the upper end of the fjord. On 17 October 2015 about 180 million tonnes of rock slid into the fjord at up to 162 km/h, causing a megatsunami that ran up to about 193 m on the opposite slope.

The glacier is named after John Tyndall (1820–1893), a British physicist, natural philosopher and glaciologist. His name links this Alaskan ice field to nineteenth-century British science.

Access to the glacier is only by bush plane, as the remote location has no road access. Visitors should bring warm clothing and sturdy equipment since weather can change quickly and ice conditions are challenging.

On 17 October 2015, about 180 million tonnes of rock slid into Taan Fjord at up to 162 km/h, sending a megatsunami that ran roughly 193 m up the opposite slope and still stood 15 m high at the fjord mouth, 17 km away.