Civil aviation spokesman Anders Stalhammar said the plane was on its way from Oslo, Norway, to Stockholm when passengers smelled smoke, and the pilot decided to bring the plane down in Vasteras, about 70 miles west of Stockholm.
"My understanding is that there was quite a lot of smoke in the cabin," Stalhammar said.
Local police said it was unclear how much smoke was in the cabin, and what caused it, but that the passengers had been wearing oxygen masks when the plane landed.
"A couple of them were shocked but no one was injured," police spokesman Borje Stromberg said. "We breathed a sigh of relief that everything went well."
More than a dozen rescue and police vehicles responded as the plane was evacuated on the runway, he said. The plane was later towed to the airport terminal for inspections.
Hultberg said all the passengers were safe and SAS was looking for ways to transport them to Stockholm later Friday.