| Katarzyna Ostrogska | |
| House-Type: | Szlachta |
| Noble Family: | Ostrozky |
| Coa: | Ostrogski |
| Father: | Konstanty Wasyl Ostrogski |
| Mother: | Zofia Tarnowska |
| Spouse-Type: | Consort |
| Issue: | Janusz Radziwiłł |
| Birth Date: | 1560 |
| Death Place: | Vilnius |
| Princess | |
| More: | no |
| Noble Family: | Ostrogski |
Princess Katarzyna Ostrogska (1560–1579) was a Ruthenian noblewoman. She was famed for the Siege of Dubna in 1577, which was sieged by nomads with the purpose of take to her prisoner.
She was the second of four wives of Krzysztof Mikołaj Radziwiłł,[1] whom she married on 22 July 1578 in Dubno.