The referendum is being held to pre-empt plans by Britain to put any agreement reached with Spain to a vote.
The two countries are currently in high-level talks, but many Gibraltarians are deeply opposed to sharing sovereignty with Madrid.
"The question put to a referendum will be limited to the single issue of joint or shared sovereignty, " a Gibraltar government statement said, adding that the exact wording would be announced later.
Britain has said it will not recognise any referendum called unilaterally by Gibraltar's government.
'Eccentric idea'
In July, UK Foreign Secretary Straw provoked outrage in Gibraltar when he said London was willing to share sovereignty with Spain, but he said the final decision would rest with the people of Gibraltar.
He has also described the idea of a referendum organised by the Gibraltarians themselves as "a rather eccentric, rather expensive idea to tell us what we knew already".
But Gibraltar Chief Minister Peter Caruana says it is unacceptable that people should be consulted once an agreement with Spain had been reached.
"The government believes that the sovereignty of Gibraltar should not be negotiated against our wishes and that the British government should not enter into political agreements with Spain on sovereignty without our consent," he said in the government statement.
Britain's opposition Conservative Party has backed Gibraltar's plans for a referendum.
"I believe they will massively reject the current dishonourable proposition to share sovereignty and hope that after that rejection Jack Straw will finally accept that the current negotiations on sovereignty should be ended," Shadow Foreign Secretary Michael Ancram said.
Gibraltar, a tiny area on the southern tip of Spain with a population of less than 30,000, was captured by Britain in the 18th century.
It was made a colony in 1830 and was given self-government with ties to the UK in 1969.