The Serdi are a Celtic tribe inhabiting Thrace.

They are located around Serdika, which reflects their ethnonym.

They would have established themselves in this area during the Celtic migrations at the end of the 4th century BCE, though there is no evidence for their existence before the 1st century BECCESerdi are among traditional tribal names reported into the Roman era.

They are gradually Thracianized over the centuries but retain their Celtic character in material culture up to a late date.