| Lasosna | |
| Name Other: | Łosośna |
| Mouth Location: | Neman |
| Mouth Coordinates: | 53.6777°N 23.7781°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Poland, Belarus |
The Lasosna, Lasasyanka (be|Ласосна, Ласасянка), pl|'''Łosośna'''[1] [2] is a river in Poland (Sokółka County) and Belarus (Hrodna and Hrodna district). Of the river's 46 km length, 24 km is in Poland and the rest in Belarus. It is a left-bank tributary of the Neman.