The West Fork of Oak Creek Canyon is one of several steep-walled canyons etched into the Mogollon Rim of central Arizona. The mouth of the canyon is located 15 km north of Sedona and 30 km south of Flagstaff along highway 87A. Perennial water, an elevation range of 500 m (1700 ft), and varying degrees of slope and aspect have created a mosaic of habitat types possessing a rich species diversity concentrated in an area of only 2,030 hectares (20.3 km2, 7.85 mi2). In recognition of the biological value of the canyon, the lower six miles have been designated as the Oak Creek Canyon Research Natural Area. The rich biota and majestic scenery of the West Fork Trail that travels the length of the lower three miles of the creek have also contributed to it becoming one of the most popular recreational hikes in the Oak Creek / Sedona area. This study has identified a total of 492 taxa of vascular plants represented by 89 families occurring within the study site boundaries. The best-represented families are Asteraceae and Poaceae, which together represent over 28% of the total flora. The study site is home to several rare species, e.g., Cimicifuga arizonica, Erigeron saxatilis, Hedeoma diffusa, Ivesia multifoliolata, and Platanthera zothecina, which are of special concern for the U.S. Forest Service. A fern specimen of Botrychium virginianum collected in 1984 is one of the only three ever collected within the state of Arizona. This study has also added Epilobium glaberrimum as a new occurrence to the flora of Arizona. The canyon?s unique and diverse flora coupled with increasing recreational use make the West Fork an area of special interest for land managers. This study being the first documented treatment of the vascular plant flora of the entire West Fork Canyon, offers a foundation for future research and for the establishment of better management tools. Furthermore, this floristic inventory serves as a benchmark for the assessment of future environmental changes.