| Tournament details | |
|---|---|
| Country | Japan |
| Dates | 22 May – 19 December |
| Teams | 90 |
| Final positions | |
| Champions | Urawa Red Diamonds (8th title) |
| Runner-up | Oita Trinita |
| Champions League | Urawa Red Diamonds |
The 2021 Emperor's Cup (Emperor's Cup JFA 101st Japan Football Championship (Japanese: 天皇杯 JFA 第101回全日本サッカー選手権大会)) was the 101st annual Japanese national football cup tournament, which began on 22 May 2021 and ended with the final on 19 December that year.
Following the compressed format of the 2020 tournament, the 2021 Emperor's Cup was restored to its usual format, featuring 90 teams representing prefectural football associations as well as the J1 and J2 Leagues. Verspah Oita was also awarded a seeded entry as the JFA's annually designated amateur club.
Kawasaki Frontale were the defending champions. They were eliminated by Oita Trinita in the semi-finals. Urawa Red Diamonds won their eighth title and qualified for the 2022 AFC Champions League group stage.