A marine bacterium, designated $IMCC3175^T$, was isolated from a seawater sample collected off the Antarctic coast. The strain was Gram-negative, obligately aerobic, carotenoid pigment-containing, and rod-shaped bacterium that divided by binary fission. As determined by 16S rRNA gene sequence comparisons, the most closely related genera were Formosa (92.9~93.3%), Bizionia (91.6~93.2%), Gaetbulibacter (91.5~92.8%), Sediminibacter (92.7%), Yeosuana (92.6%), Subsaximicrobium (92.1~92.2%), and Gillisia (89.5~92.2%). Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain formed a monophyletic clade together with the genera Sediminibacter and Subsaximicrobium but represented an independent phyletic line in this clade of the family Flavobacteriaceae. The DNA G+C content of the strain was 37.3 mol%. The major respiratory quinone was MK-6 and the predominant cellular fatty acids were $C_{16:1}$ ${omega}7c$ and/or isO-$C_{15:0}$ 2-OH (12.8%), anteiso-$C_{15:0}$ (9.4%), and iSO-$C_{16:1}$ (9.4%). Low 16S rRNA gene sequence similarity, formation of a distinct phylogenetic branch, and several phenotypic characteristics, including a narrow range of temperature and salinity for growth, differentiated strain $IMCC3175^T$ from other related genera in the family Flavobacteriaceae. Therefore the name Antarcticimonas flava gen. nov., sp. nov. is proposed, with strain $IMCC3175^T$ (=KCCM $42713^T$ =NBRC $103398^T$) as the type strain.