Cohors tertia Alpinorum equitata ("3rd part-mounted Cohort of Alpini") was a Roman auxiliary mixed infantry and cavalry regiment.

The regiment was probably raised as one of 4–6 Alpini units recruited after the final annexation of the western Alpine regions by emperor Augustus in 15 BC.

The regiment's inscriptions have been found at the following Roman forts (in likely order of occupation): Humac; Burnum; Salona; Muć; Baratsföldpuszta (Pannonia).

[2] The names of five praefecti (regimental commanders) are preserved (none has a certain origin); four centuriones (infantry officers), and two decuriones (cavalry officers) are recorded, although only one has a certain origin (Celeia, Slovenia).

Another is from the Alpes Maritimae province, where the regiment was originally (partially) recruited.