The C-series protocol droids were protocol droids produced by Cybot Galactica during the era of the New Republic. The series was a "boutique model" extension of the 3PO-series protocol droid.
The C-series droids were manufactured on the factory moon of Telti. It was widely speculated that the C-series was introduced to cash in on the success of the 3PO-series protocol droid, and in particular the exploits of C-3PO, hero of the Rebel Alliance. These rumors were officially denied by Cybot Galactica.
The C-series comprised model numbers ranging from C-1 to C-9.