Siemowit of Masovia
Siemowit of Masovia may refer to these Masovian dukes:
- Siemowit I of Masovia, son of Konrad I of Masovia and his wife Agafia
- Siemowit II of Masovia, son of Boleslaus II of Masovia and his first wife Sophie
- Siemowit III of Masovia, son of Trojden I of Masovia and his wife Maria
- Siemowit IV of Masovia, son of Siemowit III and his wife Euphemia
- Siemowit V of Masovia, son of Siemowit IV and his wife Alexandra of Lithuania
- Siemowit VI of Masovia, a Duke of Masovia