| Matryona Ivanovna Balk | |
| Birth Name: | Modesta Mons |
| Noble Family: | Mons family |
| Spouse: | Friedrich Balk |
| Issue: | Pavel Fedorovich Balk-Polev Pyotr Fedorovich Balk Natalia Lopukhina |
| Father: | Johann Mons |
| Occupation: | State Lady |
Matryona Ivanovna Balk (;) was a courtier in Russia.[1]
Born into the Dutch Mons family, Modesta was the sister of Peter the Great's long-time mistress Anna Mons and Willem Mons, private secretary and alleged lover of Catherine I.
She was a lady-in-waiting and confidant of Catherine I of Russia, Ober-Hofmeisterin of Tsarevna Catherine Ivanovna of Russia and sister of Anna Mons. She was accused in 1718 for having assisted the empress in her love affair with her brother, Willem Mons.
She was the mother of Natalia Lopukhina, famous for the Lopukhina affair.