Dean Nicolle (born 1974), is an Australian botanist, arborist and ecologist. He is widely recognised as the leading authority on the genus Eucalyptus. Nicolle was born in Adelaide, South Australia in 1974 and developed an interest in Eucalyptus trees as a young man. After completing a Bachelor of Science at Adelaide University he went on to complete his PhD in 2008 on mallee trees at Flinders University. The standard author abbreviation D.Nicolle is used to indicate this person as the author when citing a botanical name.