| Clubname: | Nõmme Kalju U21 |
| Fullname: | Nõmme Kalju FC U21 |
| Founded: | 2003 |
| Ground: | Hiiu Stadium |
| Capacity: | 670[1] |
| Chrtitle: | President |
| Chairman: | Kuno Tehva[2] |
| Manager: | Alger Džumadil |
| League: | Esiliiga B |
| Season: | 2022 |
| Position: | Esiliiga B, 9th |
| Website: | http://www.jkkalju.ee |
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Nõmme Kalju FC U21, commonly known as Nõmme Kalju U21, or simply as Kalju U21, is a football club, based in Nõmme, Tallinn, Estonia.
Founded as Nõmme Kalju II, it is the reserve team of Nõmme Kalju, and currently plays in the Esiliiga B.
Reserve teams in Estonia play in the same league system as the senior team, rather than in a reserve team league. They must play at least one level below their main side, however, they can play in the Estonian Cup.
Winners (1): 2013
As of 1 March 2017.
| Manager | Career |
|---|---|
 Getúlio Fredo | 2011–2012 |
 Zaur Tšilingarašvili | 2013–2016 |
| Erko Saviauk | 2016–2017 |