This study presents the results of the first systematic morphostratigraphic and provenance analyses of the Pliocene-Quaternary fluvial sediments in the Celje and Drava-Ptuj intramontane basins. Based on the degree of terrace preservation, the dip of the terrace surfaces and fans, and the composition and degree of weathering of the sediments, low-, middle-and high-level terrace groups were constrained and tentatively attributed to Late Pleistocene, Middle Pleistocene and Plio-Early Pleistocene, respectively. The provenance analysis focused on the sediments from the high-level terrace (Plio-Early Pleistocene) and encompassed clast lithological analysis and microfacies analysis of the clasts. The results indicate a local provenance with relatively short transport, which is consistent with the morphology of the clasts. The source rocks of the Plio-Early Pleistocene deposits in the Celje Basin are attributed to the formations outcropping in the southern Pohorje Massif and the Upper Savinja River Valley corresponding to the paleo-Savinja. The possibility of resedimentation of the clasts from Miocene clastic sedimentary rocks located north of the Celje Basin also needs to be considered. The sediments of the Drava-Ptuj Basin originate from the Pohorje Massif, the Kozjak mountain range, and the area south of the Pohorje Massif which were deposited by the paleo-Drava and paleo-Dravinja rivers. Our study indicates that the drainage systems of the paleo-Savinja, paleo-Drava and paleo-Dravinja during the Plio-Early Pleistocene roughly correspond to those of the present day. Izvleček Predstavljamo prve sistematične analize morfostratigrafije in provenience pliocensko-kvartarnih rečnih sedimentov na območju Celjskega in Dravsko-Ptujskega medgorskega bazena. Na podlagi stopnje ohranjenosti morfologije teras, naklona terasnih površin in sestave ter stopnje preperelosti sedimentov so bili opredeljeni trije terasni nivoji in interpretirane starosti teras in vršajev. Spodnjemu terasnemu nivoju je bila interpretativno določena poznopleistocenska starost, srednjemu terasnemu nivoju srednjepleistocenska, zgornjemu terasnemu nivoju pa plio-zgodnjepleistocenska starost. Analiza provenience je bila osredotočena na sedimente višjega terasnega nivoja (pliocen-zgodnji pleistocen) in je temeljila na litološki analizi klastov in analizi mikrofaciesov klastov. Rezultati nakazujejo, da gre za lokalno provenienco proda, kar dodatno potrjujejo sedimentološka opazovanja morfologije klastov. Izvor plio-zgodnjepleistocenskih sedimentov v Celjskem bazenu so domnevno formacije, ki izdanjajo na območju južnega Pohorja in Zgornjesavinjske doline, pri čemer pa moramo upoštevati