Teifiside Rural District existed in Cardiganshire, Wales from 1935 until 1974. It replaced the earlier rural districts of Llandyssil and Cardigan. The district faced the Irish Sea and was bordered on the northeast and east by Aberyaeron Rural District, and on the south by the counties of Carmarthenshire and Pembrokeshire. (See Ordnance Survey Map of Cardiganshire, 1931-1944)
Parishes
Parish Name | Type of Parish | Duration | Notes
| Aberporth | Parish (ancient), Civil parish | 1935-1974 |
| Betws Ifan | Parish (ancient), Civil parish | 1935-1974 |
| Bryn Gwyn | Parish (ancient), Civil parish | 1935-1974 |
| Cardigan Island | Extra parochial area | 1935-1974 |
| Ferwig | Parish (ancient), Civil parish | 1935-1974 | also known as Y Ferwig and Verwig (renamed in 1934)
| Llandyfriog | Parish (ancient), Civil parish | 1935-1974 |
| Llandygwydd | Parish (ancient), Civil parish | 1935-1974 |
| Llandysul | Parish (ancient), Civil parish | 1935-1974 |
| Llangoedmor | Parish (ancient), Civil parish | 1935-1974 |
| Llangrannog | Chapelry, Parish (ancient), Civil parish | 1935-1974 |
| Llangynllo | Parish (ancient), Civil parish | 1935-1974 |
| Llanfairorllwyn | Parish (ancient), Civil parish | 1935-1974 |
| Penbryn | Parish (ancient), Civil parish | 1935-1974 |
| Tredreyr | Parish (ancient), Civil parish | 1935-1974 | also known as Troedyraur
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