The aim of this research was to study the population structure of an exotic palm, Roystoneaoleracea (Arecaceae), map its spatial distribution and investigate its invasive status in an Atlantic forest wetland. A total of 130 live and 7 dead standing palms ≥10 cm DBH were sampled. Data showed a trend towards population expansion, with most seedlings and saplings occurring within a radius of ~12 m from the mother plants but some larger trees (DBH >10 cm) up to 440 m from the parents. This exotic species is established and has the potential to become invasive, especially near wetlands. Its control or eradication should be undertaken and we suggest the immediate removal of reproductive individuals, and constant monitoring of young individuals leading to their future removal. Use of this species as an ornamental should be made with care to prevent or reduce possible harmful effects of this exotic and potentially invasive species in Brazilian wetlands.