Augustus Welby Northmore Pugin (1 March 1812 – 14 September 1852) was an English architect, designer, artist and critic, chiefly remembered for his pioneering role in the Gothic Revival style; his work culminated in the interior design and "Big Ben" clock tower of the Palace of Westminster. Pugin designed many churches in England, and some in Ireland and Australia. Pugin was the father of E. W. Pugin and Peter Paul Pugin, who continued their father's architectural firm as Pugin and Pugin.

Pugin was the son of a French draughtsman, Auguste Pugin, who had come to England as a result of the French Revolution and had married Catherine Welby of Lincolnshire. Augustus was born at his parents' house in Bloomsbury. He learned drawing from his father, and for a while attended Christ's Hospital.

In 1831, aged nineteen, he married the first of his three wives, Anne Garnet. Anne died a few months later in childbirth, leaving him with a daughter. He had a further six children, including the architect Edward Pugin, by his second wife, Louisa Burton, who died in 1844. His third wife, Jane Knill, kept a journal of their married life together, between their marriage in 1848 and his death; it was later published. Their son was Peter Paul Pugin.