1981 King Cup
The 1981 King's Cup was the 23rd season of the knockout competition since its establishment in 1956. Al-Hilal were the defending champions but were defeated by Al-Nassr in the final. Al-Nassr won their 3rd title overall and first since 1976.Bracket
Source: The matches of the Round of 32 were held on 15, 16 and 17 April 1981.
| Home team | Score | Away team |
| Al-Nassr | 14–0 | Al-Amal |
| Al-Ahli | 4–1 | Al-Tai |
| Al-Ettifaq | 6–1 | Al-Fateh |
| Al-Ta'alof | 1–2 | Al-Raed |
| Al-Shate'e | 5–2 | Al-Nakhil |
| Al-Ittihad | 5–1 | Al-Arabi |
| Ohod | 2–4 | Al-Shabab |
| Al-Riyadh | 7–0 | Al-Watani |
| Hajer | 1–3 | Al-Faisaly |
| Al-Wehda | 12–0 | Al-Dera'a |
| Al-Hilal | 11–1 | Al-Qala |
| Al-Ansar | 0–0 | Al-Nahda |
| Al-Jabalain | 2–0 | Al-Taawoun |
| Al-Rabe'e | 0–7 | Al-Qadsiah |
| Al-Khaleej | 2–4 | Al-Rawdhah |
| Al-Shoulla | 1–2 | Al-Kawkab |
The Round of 16 matches were held on 22, 23 and 24 April 1981.
| Home team | Score | Away team |
| Al-Kawkab | 1–3 | Al-Ettifaq |
| Al-Nahda | 5–0 | Al-Raed |
| Al-Qadsiah | 2–0 | Al-Jabalain |
| Al-Ittihad | 1–0 | Al-Shabab |
| Al-Hilal | 3–1 | Al-Wehda |
| Al-Nassr | 1–0 | Al-Ahli |
| Al-Riyadh | 2–0 | Al-Faisaly |
| Al-Shate'e | 1–2 | Al-Rawdhah |
Quarter-finals
The Quarter-final matches were held on 30 April and 1 May 1981.
| Home team | Score | Away team |
| Al-Rawdhah | 1–2 | Al-Ittihad |
| Al-Qadsiah | 1–5 | Al-Nassr |
| Al-Riyadh | 0–2 | Al-Hilal |
| Al-Ettifaq | 3–1 | Al-Nahda |
Semi-finals
The four winners of the quarter-finals progressed to the semi-finals. The semi-finals were played on 7 and 8 May 1981. All times are local, AST.Final
The final was played between Al-Nassr and Al-Hilal in the Youth Welfare Stadium in Riyadh. This was Al-Nassr's 6th final and Al-Hilal's 7th final. This was the first meeting between these sides in King Cup finals.