Centaurea golestanica Akhani & Wagenitz (Compositae), Eriocycla ghafooriana Akhani (Umbelliferae), Plantago podlechii Akhani (Plantaginaceae,) and Seseli tortuosum L. subsp. kiabii Akhani (Umbelliferae) are described as new from Golestan National Park, NE Iran. The following species are new additions to the Iranian flora from that area: Allium vavilovii Popov & Vved., Alyssum alyssoides (L.) L., Atraphaxis seravschanica Pavlov, Carex pseudocyperus L., Ceratophyllum submersum L., Euphorbia humilis C.A. Mey. ex Ledeb., Gagea glacialis K. Koch, Lactuca georgica Grossh., Linosyris vulgaris Cass. ex Less., Myosotis alpestris F.W. Schmidt, Myosotis arvensis (L.) Hill, Myosotis minutiflora Boiss. & Reuter, Potamogeton natans L., Rumex caucasicus Rech. f. and Vicia cassubica L. Details on the habitat and associated species are given based on field studies and phytosociological relevés. Maps of distribution within the Park of all species and illustrations or photographs are given for some of the taxa concerned.