The 349-seat parliament gave the green light to the centre-right coalition's proposal to extend the mission beyond a June 22 expiry date, with 230 votes in favour, 18 opposed and 20 abstaining. The remaining 81 lawmakers were absent.
The approval was widely expected after Foreign Minister Carl Bildt announced last week that the government and the two major opposition parties, the Green and Social Democrat parties, had reached an agreement on the extension.
The far-right Sweden Democrats and the Left Party (until 1990 called the Communist Left Party) opposed the move.
According to the plan, Sweden, which currently has eight Gripen fighter jets helping enforce the no-fly zone over Libya, will reduce the number to five but also lift restrictions on what kind of surveillance missions they can conduct.
"We are also opening the door for the air surveillance to continue, even during a ceasefire," Bildt said when he presented the plan on June 8.
The mission will also be broadened to include Swedish soldiers specially trained to operate on board ships, who will be under British command.
Sweden, which is not a member of NATO, announced in March it would participate in the NATO-led air campaign against Moamer Kadhafi's forces but said its warplanes would not carry out ground strikes - a condition also imposed under the new plan.