Thomas Ignatius Maria Forster FRAS FLS (9 November 1789 – 2 February 1860) was an English astronomer, physician, naturalist and philosopher.

He published pamphlets on a wide variety of subjects, including morality, Pythagorean philosophy, bird migration, Sati, and "phrenology", a term that he coined in 1815.

[3] Two years before, he had married Julia, daughter of Colonel Mark Beaufoy, and taken up residence at Spa Lodge, Tunbridge Wells.

Here he undertook a series of researches on the influence of atmospheric conditions on diseases, and particularly on cholera which also involved a balloon ascent in April 1831.

Forster accompanied Spurzheim to Edinburgh, where he communicated a paper on the comparative anatomy of the brain to the Wernerian Society.

On his return to London he published a sketch of Gall and Spurzheim's system, which, like many of his writings, appeared in the Pamphleteer, together with an essay on the application of the organology of the brain to education.