A Sin tax is a euphemism for a tax specifically levied on certain generally socially-proscribed goods - usually alcohol and tobacco. Sin taxes are often enacted for special projects - American cities and counties have used them to pay for stadiums - when increasing income or property taxes would be politically inviable.

Some jurisdictions have also levied taxes on illegal drugs. Whether this actually qualifies as a sin tax is rather questionable, since such taxes are generally intended to create an additional punishment for trading, possession or consumption of illegal drugs rather than to raise revenue.

See: Pigovian tax