An election to Llanelli Borough Council was held in May 1991.
[1] It was preceded by the 1987 election and followed, as a result of local government reorganisation in Wales and the formation of unitary authorities, by the Carmarthenshire County Council election of 1995.
On the same day there were elections to the other district local authorities and community councils in Wales.
A by-election was held in the Hendy ward following the death of Labour councillor Len McDonagh.
[2] The contest was won by a single vote by Plaid Cymru candidate Gwyn Hopkins, who had previously served as a member of Dyfed County Council from 1977 until 1981.