William Tyler Olcott (January 11, 1873–July 6, 1936) was an American lawyer and amateur astronomer.

During 1905 while vacationing in Rhode Island, a friend of Clara introduced him to the stars and constellations.

[2] In 1909, after attending a lecture by Edward Charles Pickering, he developed an interest in observing variable stars.

In 1911, he co-founded the American Association of Variable Star Observers (AAVSO).

[3] Olcott also wrote six books to popularize the field of amateur astronomy.