The Borough of Llanelli was one of thirty-seven local government districts in Wales from 1974 to 1996. It was the smallest of six districts in the newly-created county of Dyfed, and was formed under the Local Government Act 1972 by a merger of the municipal boroughs of Llanelli and Kidwelly, Burry Port urban district and Llanelli Rural District all in the former administrative county of Carmarthenshire. The district was governed by Llanelli Borough Council which was based in the town of Llanelli.
The coat of arms with the motto 'Ymlaen Llanelli' was transferred from the former municipal borough to the Llanelli Borough Council by Order in Council in 1975. Llanelli Town Council, which covers the same area as the former municipal borough, was granted a new coat of arms in 1981.