The 1965–66 FAW Welsh Cup is the 79th season of the annual knockout tournament for competitive football teams in Wales.
| Tournament details | |
|---|---|
| Country | Wales |
| Final positions | |
| Champions |  Swansea Town |
| Runner-up |  Chester |
Key
editLeague name pointed after clubs name.
Fifth round
editTen winners from the Fourth round and six new clubs.
| Tie no | Home | Score | Away |
|---|---|---|---|
| 1 | Chester (FL D4) | 4–1 | Wrexham (FL D4) |
Sixth round
edit| Tie no | Home | Score | Away |
|---|---|---|---|
| 1 | Newport County (FL D4) | 2–2 | Chester (FL D4) |
| replay | Chester (FL D4) | 2–0 | Newport County (FL D4) |
Semifinal
edit| Tie no | Home | Score | Away |
|---|---|---|---|
| 1 | Swansea Town (FL D3) | 3–1 | Merthyr Tydfil (SFL) |
| 2 | Bangor City (CCL) | 0–3 | Chester (FL D4) |
Final
editReplay were held at Chester.
| Tie no | Home | Score | Away |
|---|---|---|---|
| 1 | Swansea Town (FL D3) | 3–0 | Chester (FL D4) |
| Chester (FL D4) | 1–0 | Swansea Town (FL D3) | |
| replay | Chester (FL D4) | 1–2 | Swansea Town (FL D3) |
