William Tailer (February 25, 1675/6 – March 1, 1731/2) was a military officer and politician in the Province of Massachusetts Bay. Born into the wealthy and influential Stoughton family, he twice married into other politically powerful families. He served as lieutenant governor of the province from 1711 until 1716, and again in the early 1730s. During each of these times he was briefly acting governor. He was a political opponent of Governor Joseph Dudley, and was a supporter of a land bank proposal intended to address the province's currency problems. During his first tenure as acting governor he authorized the erection of Boston Light, the earliest lighthouse in what is now the United States.