John Stanley Plaskett CBE FRS[2] (November 17, 1865 – October 17, 1941) was a Canadian astronomer.

He worked as a machinist, and was offered a job as a mechanician at the Department of Physics at the University of Toronto, constructing apparatus and assisting with demonstrations during lectures.

His formal astronomical career did not start until 1903, when he was appointed to the staff at Dominion Observatory in Ottawa, Ontario.

He measured radial velocities and studied spectroscopic binaries, and performed the first detailed analysis of galactic structure.

[4] An authoritative biography of JS Plaskett was published in 2018,[5] coinciding with the centennial of the Dominion Astrophysical Observatory.