Gateway House in Manchester, England, is a modernist office block above a row of shops designed by Richard Seifert & Partners and completed in 1969.

The building, which differed from much of Seifert's contemporary work in that it departed from the bare concrete brutalist style which had become his trademark, was nicknamed the "lazy S" and was reputedly designed as a doodle.

It is considered to be one of Siefert's most loveable buildings,[2] commanding respect from Clare Hartwell, who described it as a very impressive long, sweeping, undulating façade, the horizontals stressed throughout.

An office block with ground floor retail space on Ducie Street and a gym behind the Seifert building would be the second phase of the development.

A major redevelopment of the neighbouring Piccadilly Station and the surrounding area was proposed to complement the planned construction of the High Speed 2 (HS2) railway line to Manchester.