Sebastian Siedler (born 18 January 1978 in Leipzig) is a former racing cyclist from Germany, who last rode for UCI Continental team Vorarlberg–Corratec.

He had a successful track career prior to turning to road bicycle racing, winning Team Pursuit at the 2000 UCI Track Cycling World Championships in Manchester.

He turned professional in 2004 with Team Wiesenhof, and spent two seasons there before moving to Team Milram for two seasons.

He rode in the 2006 Vuelta a España, finishing 127th overall.

This biographical article related to a German cycling person born in the 1970s is a stub.