Marcus Stoinis made the highest individual BBL score of 147 not out from 79 balls, in a total of 1/219 posted by the Stars. The Sixers made 7/175 in reply.
Stoinis shared an opening stand of 207 with Hilton Cartwright (59 from 40), the highest partnership in BBL history.
While Sixers captain Moises Henriques (41 from 25) was at the crease, the men in magenta kept pace with the required run rate, but the loss of regular wickets was pivotal.
Left-arm quick Ben Dwarshuis showed his power with bat in hand, towards the end, hitting 42 not out from just 17 balls, including three sixes.
Despite the loss, the Sixers maintain second place on the BBL|09 ladder with their next match against the Hobart Hurricanes at the SCG on Thursday night.