This paper presents new data on the diversity of Lactuca L. in Turkey based on recent collections made during revisional work. Lactuca leucoclada Rech. f. & Tuisl is newly recorded for Turkey, and for Lactuca viminea (L.) J. Presl. & C. Presl. and Lactuca quercina L., the presence of two distinct subspecies each in Turkey, L. viminea subsp. viminea and L. viminea subsp. ramosissima (All.) Arcang., and L. quercina subsp. quercina and L. quercina subsp. wilhemsiana (DC.) Ferakova, respectively, are reported. The presence of Lactuca macrophylla (Willd.) A. Gray, so far only doubtfully reported from Turkey, is confirmed in the present study. Emended descriptions, type information, updated distribution maps, and microphotographs of the taxonomically important achene features are presented for the studied taxa.