Strain NHI-24(T) was isolated from forest soil by a polycarbonate membrane transwell plate. It is a Gram-negative, rod-shaped, non-motile, non-spore-forming bacterium. Phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain NHI-24(T) is closely related to members of the genus Niabella: N. drilacis E90(T) (97.7 %), N. tibetensis 15-4(T) (96.7 %), N. aurantiaca R2A15-11(T) (96.5 %), N. hirudinis E96(T) (95.8 %), N. soli JS13-8(T) (94.7 %), N. ginsengisoli NBRC106414(T) (94.4 %), and N. yanshanensis CCBAU 05354(T) (94.2 %). Growth temperatures range widely, from 15 to 37 °C, with 30 °C as the optimum. Salt tolerance ranges from 0 to 2 %. The strain grows at pH 6.5-11.0, with an optimal range of pH 7.0-9.5. Cells produce flexirubin-type pigments, and the predominant menaquinone is MK-7. The major fatty acids of strain NHI-24(T) are iso-C15:0 (36.72 %), iso-C15:1 G (20.8 %), and summed feature 3 (C16:1 ω7c/C16:1 ω6c; 15.2 %). DNA-DNA hybridization values between strain NHI-24(T) and members of the genus Niabella range from 37 to 53 %. Based on these results, it is proposed that strain NHI-24(T) represents a novel species of the genus Niabella with the name Niabella thaonhiensis (= KACC 17215(T) = KEMB 9005-018(T) = JCM 18864(T)).