James Whitbread Lee Glaisher (5 November 1848, in Lewisham — 7 December 1928, in Cambridge) was a prominent English mathematician and astronomer.

[2][3] He was born in Lewisham in Kent on 5 November 1848 the son of the eminent astronomer James Glaisher and his wife, Cecilia Louisa Belville.

He became somewhat of a school celebrity in 1861 when he made two hot-air balloon ascents with his father to study the stratosphere.

Influential in his time on teaching at the University of Cambridge, he is now remembered mostly for work in number theory that anticipated later interest in the detailed properties of modular forms.

[2][3][7] When George Biddell Airy retired as Astronomer Royal in 1881 it is said that Glaisher was offered the post but declined.