Hornworts are globally the least diverse bryophyte group with respect to species number, with only eight species known from Europe. As for Croatia, only two species are listed in the available literature, with most recent record being more than 85 years old. Our study carried out in Central Croatia identified three new species for the hornwort flora, including two new genera – Notothylas Sull. ex. A. Gray and Anthoceros L. Our finding of very rare Natura 2000 species Notothylas orbicularis (Schwein.) A. Gray, reported hitherto only from four Central European countries, is the first in Southeast Europe and the southernmost in Europe. Furthermore, we recorded Anthoceros agrestis Paton and Phaeoceros carolinianus (Michx.) Prosk., which are either very rare or, more likely, overlooked and understudied in Southeast Europe.