Siegfried Reissek was an Austrian naturalist and botanist who specialized in spermatophytes. He is known for his studies involving plant anatomy and histology.
From 1837 to 1841 he was a student at the University of Vienna. He worked as assistant curator at the Royal Botanical Collection in Vienna between 1845 and 1867, when he was appointed head curator; and from 1848 was a member of the Vienna Academy of Sciences. He circumscribed numerous plant taxa, including the genus Stenanthemum. The plant genus Reissekia commemorates his name.