The current study attempts to investigate the distribution of ascidian species collected from eight stations located along the eastern coasts of Aegean Sea, Turkey. Forthis purpose, field studies wereconducted inJuly 2016. This study revealed the occurrence of 14 ascidian species belonging to 7 families and 12 genera. The invasive species Polyclinum constellatum Savigny, 1816 isreported for the first time from Turkish waters and for the second time in the Mediterranean Sea. Furthermore, Symplegma brakenhielmi (Michaelsen, 1904) is found as a new recordfor the Turkish Aegean Sea fauna. Knowledge about the ascidian diversity of the Turkish Seas is still incomplete andlarge-scale surveys, additional taxonomic and molecular studies are needed.