John Thomas Young Gilroy (30 May 1898 – 11 April 1985) was an English artist and illustrator, best known for his advertising posters for Guinness, the Irish stout.

Born in Whitley Bay, Northumberland, England, Gilroy attended Durham University until his studies were interrupted by World War I, during which he served with the Royal Field Artillery.

[3] He created cover designs for the Radio Times, most famously, in 1936, one depicting a laughing cat.

He was awarded and Honorary MA by Newcastle University in 1975, and was made a Freeman of the City of London in 1981.

His second marriage, in 1950, was to Elizabeth Margaret Outram Bramley who already had a daughter (Jenefer) and a son (Robin).