Dr John Armstrong (1709-1779) was a poet. He was the son of the minister of Castleton, Roxburghshire, Scotland and studied medicine, which he practised in London. He is remembered as the friend of James Thomson, David Mallet, and other literary celebrities of the time, and as the author of a poem on The Art of Preserving Health, which appeared in 1744, and in which a somewhat unpromising subject for poetic treatment is gracefully and ingeniously handled. His other works, consisting of some poems and prose essays, and a drama, The Forced Marriage, are forgotten, with the exception of the four stanzas at the end of the first part of Thomson's Castle of Indolence, describing the diseases incident to sloth, which he contributed.