William Walcot RE (10 March 1874 – 21 May 1943) was a Scottish architect, graphic artist and etcher, notable as a practitioner of refined Art Nouveau (Style Moderne) in Moscow, Russia (as Вильям Францевич Валькот).

In 1899, Walcot applied to the open contest with a draft codenamed A Lady's Head (Женская головка), earning the fourth prize and losing to Lev Kekushev.

However, Mamontov discarded the professional jury decision, and awarded the design to Walcot (Lev Kekushev later joined the team as project manager).

More than once, Walcot's original plans were changed in the process; in fact, there is little in common between the extant building and his 1899 draft (Brumfield, fig.56) – but the Lady's Head persisted in the main hall ornaments.

These buildings, soon occupied by foreign embassies, are well maintained and retain most of their original interiors: Walcot's mosaic, signed W.W., adorns the List House in Glazovsky Lane, built by Lev Kekushev.

Walcot developed his own impressionistic style in gouache and watercolour which won numerous commissions from Edwin Lutyens, Herbert Baker and Aston Webb.