| Aga siis | |
| Cover: | Juri Pootsmann Aga Siis.jpg |
| Type: | single |
| Artist: | Jüri Pootsmann |
| Album: | Jüri Pootsmann |
| Released: | 13 November 2015 |
| Recorded: | 2014 |
| Genre: | Pop |
| Length: | 3:31 |
| Label: | Universal Music Group |
| Producer: | Sten Sheripov |
| Prev Title: | Torm |
| Prev Year: | 2015 |
| Next Title: | Play |
| Next Year: | 2016 |
"Aga siis" (en|"But Then") is a song performed by Estonian singer Jüri Pootsmann. The song was released as a digital download on 13 November 2015 through Universal Music Group as the second single from his self-titled extended play. The song peaked at number 1 on the Estonian Airplay Chart.