Forest soils of the Great Smoky Mountains National Park were examined for soil algae as part of the All Taxa Biodiversity Inventory underway in that park. Soils of both mature and secondary growth forests were sampled, along with samples from rocks and tree bark. A total of 42 taxa were observed, representing Cyanobacteria (3 species), Chlorophyceae (12 species), Trebouxiophyceae (18 species), Ulvophyceae (3 species), Klebsormidiophyceae (1 species), Zygnematophyceae (2 species), Tribophyta (3 species), Eustigmatophyta (1 species), Euglenophyta (1 species), and Dinophyta (1 species). Twenty new taxa records for the park were established.