Ormrod Maxwell Ayrton FRIBA (1874–18 February 1960), known as Maxwell Ayrton, was a Scottish architect. He spent most of his adult life working in London and designed houses, public buildings, and bridges.
Ayrton began his career in 1890 as an articled apprentice to Harry Beswick of Chester, remaining with him until 1897. He then moved to London, where from 1897 to 1899 he was an assistant first to Richard Creed, then to William Alfred Pite, and finally to Edwin Landseer Lutyens. During these years he studied at the South Kensington Schools of the Royal College of Art. He passed the Royal Institute of British Architects qualifying examination and was admitted an Associate on 30 November 1903, having been proposed by Pite, John William Simpson and Lacy William Ridge.
Ayrton was in practice on his own from 1899, and in 1903 was at 14, Belsize Park Gardens, London. One of his early buildings was a house called Hall Ingle, at Heath End, Checkendon (1902), "...by Mr. O. Maxwell Ayrton, for, and decorated by, Arthur Hacker, Esq., ARA". Hacker painted Ayrton's wife and exhibited the portrait at the Royal Academy in 1902.
In 1905, Ayrton joined John William Simpson's practice, and from then on he carried out most of the firm's design work. He became a partner in the firm in 1910 and was elected a Fellow of the Royal Institute of British Architects in 1920, having been proposed by his old master Lutyens and by Sir Aston Webb, who at the time was President of the Royal Academy.