| Club: | Aberdeen F.C. |
| Season: | 1920–21 |
| Manager: | Jimmy Philip |
| Mgrtitle: | Manager |
| League: | Scottish Football League |
| League Result: | 11th |
| Cup1: | Scottish Cup |
| Cup1 Result: | Third round |
| League Topscorer: | Peter Fisher (14) |
| Season Topscorer: | Peter Fisher (14) |
| Highest Attendance: | 24,000 vs. Celtic, 28 August 1920 |
| Lowest Attendance: | 8,500 vs. Kilmarnock, 12 March 1921 |
| Prevseason: | 1919–20 |
| Nextseason: | 1921–22 |
| Chairman: | William Philip |
Aberdeen F.C. competed in the Scottish Football League and Scottish Cup in season 1920–21.
Aberdeen finished in 11th place out of 22 clubs in the Scottish Football League, an improvement on the previous season's finish of 17th. In the cup, they lost out to local rivals Dundee after a second replay in the third round. Peter Fisher finished as the club's top scorer with 14 goals.
| Match Day | Date | Opponent | H/A | Score | Aberdeen Scorer(s) | Attendance |
|---|---|---|---|---|---|---|
| 1 | 21 August | Dundee | A | 1–1 | Fisher | 5,000 |
| 2 | 24 August | Rangers | A | 1–2 | Thomson | 20,000 |
| 3 | 28 August | Celtic | H | 1–2 | Wright | 24,000 |
| 4 | 30 August | Third Lanark | A | 1–3 | Connon | 12,000 |
| 5 | 4 September | Albion Rovers | A | 2–0 | Fisher, Rankine | 8,000 |
| 6 | 8 September | Clyde | H | 3–0 | Thomson, Fisher, Rankine | 14,000 |
| 7 | 11 September | Ayr United | H | 0–0 | 16,000 | |
| 8 | 15 September | Hamilton Academical | H | 3–1 | Wright (2), MacDonald | 10,000 |
| 9 | 18 September | Morton | A | 1–6 | Grant | 7,000 |
| 10 | 25 September | Rangers | H | 1–1 | Fisher | 21,800 |
| 11 | 27 September | Queen's Park | H | 2–2 | Fisher (2) | 12,000 |
| 12 | 2 October | Clydebank | A | 1–1 | Thomson | 5,000 |
| 13 | 9 October | Hibernian | H | 0–1 | 13,500 | |
| 14 | 16 October | Hamilton Academical | A | 2–0 | Thomson, Rankine | 6,000 |
| 15 | 23 October | Raith Rovers | H | 1–0 | Connon | 13,000 |
| 16 | 30 October | Clyde | A | 0–2 | 6,000 | |
| 17 | 6 November | Third Lanark | H | 0–1 | 12,500 | |
| 18 | 13 November | Heart of Midlothian | A | 0–0 | 15,000 | |
| 19 | 20 November | St Mirren | H | 3–1 | Rankine (2), Flanagan | 14,000 |
| 20 | 27 November | Dumbarton | A | 1–0 | Middleton | 2,500 |
| 21 | 4 December | Airdrieonians | H | 1–0 | Thomson | 12,000 |
| 22 | 11 December | Kilmarnock | A | 0–1 | 6,000 | |
| 23 | 18 December | Motherwell | H | 1–1 | Flanagan | 12,500 |
| 24 | 25 December | Partick Thistle | H | 0–3 | 13,000 | |
| 25 | 1 January | Dundee | H | 0–0 | 20,000 | |
| 26 | 3 January | Ayr United | A | 2–2 | Connon, Rankine | 6,000 |
| 27 | 8 January | Raith Rovers | A | 0–1 | 9,000 | |
| 28 | 15 January | Falkirk | H | 1–1 | Fisher | 11,000 |
| 29 | 22 January | Clydebank | H | 4–0 | Milne, Middleton, Flanagan (2) | 10,500 |
| 30 | 29 January | Celtic | A | 1–3 | Fisher | 15,000 |
| 31 | 8 February | St Mirren | A | 1–1 | MacDonald | 7,500 |
| 32 | 26 February | Morton | H | 0–1 | 9,000 | |
| 33 | 5 March | Hibernian | A | 3–2 | Middleton, Mackie, Own goal | 6,500 |
| 34 | 9 March | Airdrieonians | A | 2–5 | Connon, Mackie | 3,000 |
| 35 | 12 March | Kilmarnock | H | 1–1 | Hutton | 8,500 |
| 36 | 19 March | Queen's Park | A | 2–0 | Fisher, Own goal | 6,500 |
| 37 | 26 March | Dumbarton | H | 2–0 | Fisher (2) | 10,000 |
| 38 | 2 April | Partick Thistle | A | 2–2 | Fisher, Flanagan | 12,000 |
| 39 | 9 April | Heart of Midlothian | H | 5–2 | Wright, MacLachlan, Connon, Fisher, Thomson | 12,500 |
| 40 | 16 April | Motherwell | A | 0–4 | 8,000 | |
| 41 | 23 April | Falkirk | A | 0–0 | 7,000 | |
| 42 | 30 April | Albion Rovers | H | 1–0 | Fisher | 11,500 |
See main article: 1920–21 Scottish Cup.
| Round | Date | Opponent | H/A | Score | Aberdeen Scorer(s) | Attendance |
|---|---|---|---|---|---|---|
| R2 | 5 February | Kilmarnock | A | 2–1 | Connon, MacDonald | 11,000 |
| R3 | 19 February | Dundee | A | 0–0 | 30,000 | |
| R3 R | 23 February | Dundee | H | 1–1 | Grosert | 20,000 |
| R3 2R | 1 March | Dundee | N | 0–2 | 10,000 | |
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