This paper reports the results of an inventory of the vascular plants at the Red Slough and Grassy Slough Wildlife Management Areas in southeastern Oklahoma. A total of 426 taxa of vascular plants in 269 genera and 106 families was collected. The most species were collected from the families Asteraceae (53), Poaceae (42), Cyperaceae (31), and Fabaceae (27). Ninety-nine species were annuals or biennials, and 328 perennials. Ninety-three species of woody plants were present. Twenty-eight species not native to North America were collected representing 6.6% of the flora. Thirty species tracked by the Oklahoma Natural Heritage Inventory were found. The first occurrence in Oklahoma of Anoda cristata, Malvaceae, is reported in this study.