Otto Wilhelm Masing

3 March] 1832 in Äksi, Kreis Dorpat, then Livland Governorate, now Estonia) was a clergyman, writer, journalist, linguist, notable early Estophile and a major advocate of Estonian commoners' rights, especially regarding education.

Masing was born in 1763 in the village of Lohusuu, Kreis Dorpat (then part of Russian Empire, now Estonia).

His father Kristian Masick was a local ethnic Estonian Lutheran clergyman, and mother Anna Ludovica von Hildebrandt was a noblewoman of German descent.

Masing's first employment after concluding his studies was as private tutor at the manor in Püssi (Neu-Isenhof) for the children of the nobleman Otto Magnus von Toll.

Among other linguistic contributions, Masing is credited with creating the letter õ to denote an Estonian phoneme not found in other related languages.