40 (Ulster) Signal Regiment (Volunteers) was a Territorial Army regiment in the Royal Corps of Signals in the British Army.

The regiment formed part of 2 (National Communications) Signal Brigade, providing military communications for national operations.

The regiment did not have an internal security role in Northern Ireland.

The Regiment was formed 1 April 1967 in Belfast by the amalgamation of 66 Signal Regiment (TA), 81 Signal Regiment (AER) and 302 Signal Squadron.

[1] Due to the reduction in Territorial Army Royal Signals units, as a result of the Strategic Review of Reserves,[2] the regiment was disbanded on 31 March 2010.