Background Phytoliths (microscopic opal silica particles produced in and between the cells of many plants) are a very resilient, often-preserved type of microfossil and today, phytolith analysis is widely used in palaeoenviron-mental studies, botany, geology and archaeology. To date there has been little standardization in the way phytoliths are described and classified. Scope This paper presents the first International Code for Phytolith Nomenclature (ICPN), proposing an easy to follow, internationally accepted protocol to describe and name phytoliths.