The C. Donald Shane telescope is a 120-inch (3.05-meter) reflecting telescope located at the Lick Observatory in San Jose, California. It was named after astronomer C. Donald Shane in 1978, who led the effort to acquire the necessary funds from the California Legislature, and who then oversaw the telescope's construction. It is the largest and most powerful telescope at the Lick Observatory, and was the second-largest optical telescope in the world when it was commissioned in 1959.

The Shane's mirror started as a 10,000-pound Corning Labs glass test blank for the Palomar Observatory's 200-inch (5-m) Hale telescope (in north San Diego County, California), but was sold below cost ($50,000) by Caltech to the Lick Observatory. It was then transported to Mount Hamilton, where the blank was ground and polished by the observatory.

The telescope is noted for having three foci, prime focus, Cassegrain focus, and coudé focus. After several decades of celebrated use, it was also fitted with an early adaptive optics system.