The distribution of toxic and potentially toxic phytoplankton species in relation to environmental factors was investigated from November 2014 to April 2015 in Boka Kotorska Bay, in the south -eastern part of the Adriatic Sea. The RDA analysis of environmental parameters showed that the system is mostly temperature-driven. The phytoplankton community was mainly composed of diatoms and less with dinoflagellates. Pseudo-nitzschia was the dominant diatom, present in 88.40 % of samples, with a maximum (of 1.85 × 10 5 cells/l). Among toxic dinoflagellates, frequent were Dinophysis acuminata (with frequency of 33.33%), D. fortii (with frequency of 23.19%) and Prorocentrum cordatum (with frequency of 21.74%). The RDA analysis showed that diatoms correlated slightly positively with nutrients and negative correlation was recorded with temperature and salinity. Dinoflagellates showed strong positive association, indicating a positive correlation with oxygen concentration, chl a, SiO4 -and NO3 -concentrations and negative correlation with temperature and salinity.