The incident took place at Un village in Kankrej tehsil of Banaskantha district yesterday, police said.
Himatsinh Chauhan (20), who belongs to Koli Thakor, an OBC community, was beaten up by members of the Darbar community when they noticed that he used 'Sinh' in his name on Facebook.
An FIR was registered under IPC sections 394 (voluntarily causing hurt in committing robbery), 395 (dacoity), and 506(b) (criminal intimidation), said Sub-Inspector A K Bharwad of the Thara police station.
"Chauhan was thrashed by a group of men after they saw that on his Facebook page he uses the suffix "Sinh" in his name. They also robbed him. We arrested six persons today," the officer said.
'Sinh' appears in Chauhan's name in the school certificate too, he said.
The incident comes close on the heels of a similar incident in the same district.
On May 27, a man was allegedly beaten up and forced to shave off his moustache for using Sinh in his name on invitation cards for a religious ceremony at Gaud village near Palanpur.
Before that, on May 22, a group of Rajputs clashed with Dalits at Dholka in Ahmedabad district over a Dalit man's decision to add `Sinh' to his name. Maulik Jadhav had announced on Facebook that he would be known as Mauliksinh Jadav henceforth, which angered some upper caste men.