Zachary Macaulay (1768-1838) was a British colonial governor, influential 18th century philanthropist, a man of evangelical piety and a supporter of William Wilberforce.

Zachary Macaulay was sent to Jamaica at the age of 16 where he finally became a manager of a plantation. Returned to England in 1792 and left for Sierra Leone in 1793, where he became its governor until resignation in 1799. He edited the Christian Observer which helped fight for the abolition of the slave trade, 1802-1816. He founded The Anti-Slavery Reporter in 1825 and was its first editor. He also held the post of Secretary to the African Institute, 1807-1812.

A member of the Clapham Sect, he helped form the Anti-Slavery Society in 1823. He married Selina Mills in 1799 and is the father of Thomas Macaulay.