BRUSSELS -- Intel Corp. appealed a billion-euro antitrust fine Wednesday. That was expected. But among the chip giant's arguments is an unlikely complaint: Its human rights were violated.

Intel isn't alone. A growing list of companies are raising the charge that the EU's vigorous antitrust watchdog is running afoul of protections afforded by European human-rights law. The companies argue they have a right to have their case heard in a court instead of an administrative body.

When...