Walter Trier (25 June 1890 in Prague – 8 July 1951 in Craigleith, near Collingwood) was a Czech-German illustrator, best known for his work for the children's books of Erich Kästner and the covers of the magazine Lilliput.

During the Second World War, Trier helped the Ministry of Information produce anti-Nazi leaflets and political propaganda.

It was run over by a tram and killed,[citation needed] and after that Trier immortalised him in his Lilliput covers; the idea was light-hearted and the settings and styles varied considerably.

Trier also created various murals: in the Kabarett der Komiker at Kurfürstendamm (1929, destroyed by the Nazis in 1933), on the liner SS Bremen (1929), and for Hoffmann–La Roche (Welwyn Garden City, 1938).

The Walter Trier Gallery at the Art Gallery of Ontario (AGO) Devoted to the work of Walter Trier features small rotating exhibitions of the artist's watercolours, drawings, paintings and sculpture along with satirical works on paper by other artists from the AGO collection.