The three others, including the alleged mastermind, were acquitted.
The works by the Norwegian artist were snatched by masked gunmen from the Munch Museum in Oslo in August 2004 and are still missing.
There are four versions of "The Scream," one of the world's most recognized painted images, showing an anguished figure against a surrealistic reddish sky.
The gunmen who stole the paintings could still be at large, since the Oslo District Court said the evidence presented during the six-week trial did not conclusively prove that any of the suspects had actually robbed the museum.
The court convicted Bjoern Hoen, 37, providing a getaway car, and sentenced him to seven years in prison. It found that Petter Tharaldsen, 34, drove the car, and sentenced him to eight years.
Petter Rosenvinge, 38, was convicted and sentenced to four years for providing the getaway car even though the court found it unlikely that he knew the exact target of the robbery.
Hoen and Tharaldsen, who immediately appealed, were also ordered to pay $123 million in compensation to the City of Oslo, which owns the paintings.
It was not immediately clear whether Rosenvinge would appeal.
Of Tharaldsen, the ruling said "he knew that the two people who ran into the museum were armed with a revolver, and would use it to threaten staff and guests to achieve the goal of the robbery."
The court said that even though witnesses had described Hoen as one of the robbery's planners, it did not consider that proven. However, it said he obtained a car for the robbers, knowing to would be used in the robbery.
Stian Skjold, 30, whom the prosecution portrayed as the mastermind, was acquitted. That was partly because his tall, thin build should have made it easy to identify him on security camera tapes, even if masked, the court said.
It also acquitted Morten Hugo Johansen, 39, the previous owner of the getaway car, saying he could not be presumed to have known that the car he sold would be used in a robbery.
Thomas Nataas, 36, who had been accused of receiving stolen property, was acquitted because the paintings had been stored without his knowledge in a bus he owns and remained there for several weeks despite his angry objections, the ruling said.
During the trial, which ended April 24, the prosecution described the theft as an attack on Norwegian culture and demanded convictions. The defendants pleaded not guilty and their lawyers called for acquittals due to lack of evidence.
Despite an international police hunt, and the offer of a $328,000 reward, the paintings have not been recovered.
Munch's emotionally charged painting style became a major influence in the birth of the 20th-century expressionist movement.
"The Scream" and "Madonna" were part of his "Frieze of Life" series, focusing on sickness, death, anxiety and love.
Munch died in 1944 at age 80.