In this study, the pollen morphology of 22 Turkish taxa (12 of which are endemic) of the taxonomically complex genus Thlaspi L. sensu lato was studied with light microscopy (LM) and scanning electron microscopy (SEM). We found that the pollen of Thlaspi are usually bilateral symmetric and anisopolar. They are prolate, subprolate, perprolate or spheroidal, with the polar axis ranging from 14.13 to 28.36 mu m and equatorial axis from 8.75 to 19.48 mu m. Pollen are usually tricolpate, but some of them are 1-2- or 4-colpate. The ornamentation of pollen of the examined taxa is usually micro or macro reticulate, and rarely foveolate. The exine thickness ranges from 1.59 to 2.75 mu m, and the intine thickness from 0.54 to 0.94 mu m. As a result of this study, some of the pollen characters such as the sizes of pollen and colpus, ornamentation of exine, apocolpidium, and shape and diameter of amb are found to be significant morphological characters for taxonomic use.