Sebastian Fleischer (born 26 December 1993 in Helsingør) is a Danish windsurfer, who specialized in Neil Pryde RS:X class.
As of November 2015, he is ranked no.
8 in the world for the sailboard class by the International Sailing Federation.
Fleischer competed in the men's RS:X class at the 2012 Summer Olympics in London by receiving a berth from the World Championships in Cadiz, Spain.
Struggling to attain a top position in the opening series, Fleischer accumulated a net score of 220 for a twenty-ninth-place finish in a fleet of thirty-eight windsurfers.