They appear in lot's of TV, books and stories - but today, pirates are a serious business.
Organised gangs take people hostage, steal money, expensive cargo and make some seas very dangerous.
But a group of politicans say the laws on what people can do to defend themselves against pirates aren't very clear.
They've asked the government to clear up how people who want to use the seas can defend themselves.
Back in October, the Prime Minister David Cameron gave permission for guards carrying guns to be allowed on ships.
But some people think this isn't a good idea - and they aren't sure if they can fight back anyway.