Edwin Seward (1853–1924) was an architect based in Cardiff, Wales.
Born in Somerset, Seward came to Cardiff aged 16 and studied at the School of Art. He began work as an assistant to architect G. E. Robinson.
Seward was one of the individuals at the centre of Cardiff's young art scene. He was President of the Cardiff Naturalists' Society (founded 1867) which was a hub of intellectual discussion. He tried unsuccessfully to establish a national institution in Cardiff for Welsh art (the Cambrian Academy of Art eventually set up in Conwy) and was a founding member of the South Wales Art Society in 1888.
By 1875 Seward was a member of the architecture firm James, Seward and Thomas and went on to build some of Cardiff's most notable buildings in the late 19th Century.
Seward designed the Turner House Gallery (1887/8) in Penarth for businessman James Pyke Thompson. He was the winning architect for the Swansea Harbour Trust Building in Swansea and he worked on the widening of the Wye Bridge in Monmouth.