It is common belief that semantic properties supervene on non-semantic properties: no two possible worlds can be non-semantic duplicates and fail to be semantic duplicates. The view enjoys somewhat of an orthodoxy status in contemporary philosophy of language and metaphysics, and is often assumed without argument. Yet, work by Stephen Kearns and Ofra Magidor has claimed that it is vulnerable to a variant of the classical arguments against the supervenience of the phenomenal on the physical. This paper does three things: (...) it clarifies what semantic supervenience is about, it responds to the objections that have been leveled against it, and provides a new battery of arguments in its favor. I argue that the thesis of semantic supervenience is safe from classical anti-supervenience arguments, and show that its rejection generates unwelcome consequences. I conclude that there are substantial reasons to embrace the received wisdom: semantic properties supervene. (shrink)