Elias Tillandz (1640–1693; born Tillander) was a Swedish medical doctor and botanist who worked in Finland.
He wrote the country's first botanical work, the Catalogus Plantarum, which was first published in 1673.
As a doctor he also prepared medicines for his patients by using his extensive knowledge of plants.
A genus of epiphytic plants, Tillandsia, was named after Tillandz by Carl Linnaeus.
This botanist is denoted by the author abbreviation Tillandz when citing a botanical name.