A bacterial strain, SD-gT, was isolated from a soil sample collected on Dokdo Island, South Korea. Cells were observed to be Gram stain negative and short rod shaped, and colonies to be pink in color. Growth of the isolate was observed at 4-30 °C, pH 6-8, and in the presence of 0-2.0% NaCl. Analysis of 16S rRNA gene sequences identified strain SD-gT as a member of the genus Mucilaginibacter in the family Sphingobacteriaceae, with high levels of sequence similarity with Mucilaginibacter terrenus ZH6T (96.9%), Mucilaginibacter lutimaris BR-3T (96.8%), Mucilaginibacter carri PR0008KT (96.8%), Mucilaginibacter gilvus F01003T (96.7%), Mucilaginibacter litoreus BR-18T (96.6%), and Mucilaginibacter terrigena 17JY9-4T (96.5%). The genomic DNA G+C content of strain SD-gT was calculated to be 40.6 mol%. The predominant respiratory quinone of the isolate was found to be MK-7; the main polar lipid was phosphatidylethanolamine; and the major fatty acids were identified as summed feature 3 (C16:1 ω7c/C16:1 ω6c; 29.0%), C15:0 iso (19.1%), C15:0 iso (28.1%), C16:0 (14.9%), and C17:0 iso 3-OH (7.4%). The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain SD-gT and M. terrenus ZH6T, M. gilvus F01003T, and M. terrigena ranged from 17.7 to 18.4% and 72.1 to 74.0%, respectively. On the basis of its phenotypic properties, genotypic distinctiveness, and chemotaxonomic features, strain SD-gT represents a novel species in the genus Mucilaginibacter, for which the name Mucilaginibacter segetis sp. nov. is proposed. The type strain is SD-gT (= KCTC 82353T = JCM 34284T).