Peter Paul Pugin (1851 – March 1904) was an English architect, son of Augustus Welby Pugin by his third wife Jane Knill. He was the half-brother of architect and designer Edward Welby Pugin.
Peter Paul Pugin was only a year old when his father died. He later began practice as the junior partner in Pugin & Pugin, the family architectural firm. The senior partner was his half-brother Edward Welby Pugin.
When Edward Welby Pugin died suddenly on 5 June 1875 as a result of overwork and 'injudicious use of chloral hydrate', the main responsibility for the practice passed to Peter Paul Pugin. Although Peter Paul's offices remained in London and Liverpool, his practice was largely Scottish, and he also maintained an office in Glasgow. Although Peter Paul's earlier churches were strongly influenced by his father and brother, by the 1880s he had developed a very recognisable curvilinear Gothic style, usually in red sandstone with elaborate altarpieces in coloured marbles.
Apart from his own works, Peter Paul Pugin completed several of the works of Edward Welby Pugin after the latter's death, in particular the church of Our Lady Star of the Sea in Workington, Cumbria. In 1889 Peter Paul Pugin was made a Knight of the Order of St. Sylvester, one of the Papal Orders of Chivalry.
Peter Paul Pugin married Agnes, the third daughter of the Catholic builder John Bird of Hammersmith in 1886. They had five children, but none entered the practice. Peter Paul died in Bournemouth in March 1904, the firm being continued by his nephew Sebastian Pugin Powell, born in 1886, the son of John Hardman Powell. Peter Paul Pugin was buried in Ramsgate.