Stefan Karlsson, born November 5, 1955, is a retired male badminton player from Sweden. He later changed name to Stefan Mellgård.
Though he played Thomas Cup singles for Sweden and won the Swedish national singles title twice, his greatest successes came in doubles. He won men's doubles at the biennial European Championships twice, with Claes Nordin in 1980 and with Thomas Kihlström in 1982. In 1983 he shared the prestigious All-England men's doubles title with Kihlström. He won the silver medal at the 1985 IBF World Championships in mixed doubles with Maria Bengtsson.