An actinomycete strain, S3-1(T), was isolated from marine sponge sample collected from the Gulf of Thailand. The strain is aerobic, Gram-positive and produced single spores at the tip of the substrate mycelium. Strain S3-1(T) contained meso-diaminopimelic acid in the peptidoglycan, whole-cell sugars were arabinose, galactose, glucose, rhamnose, ribose and xylose. The polar lipid profile of strain S3-1(T) consisted of phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides, phosphoglycolipid and unknown polar lipids. Morphological and chemotaxonomic characteristics of the strain were identified as a member of the genus Micromonospora. Phylogenetic analysis based on 16S rRNA gene sequence analysis of the strain showed similarity to Micromonospora nigra DSM 43818(T) (98.8%), Micromonospora yangpuensis FXJ6.011(T) (98.7%) and Micromonospora narathiwatensis BTG4-1(T) (98.6%). The DNA G+C content was 72.7 mol%. The phenotypic characteristics and DNA-DNA relatedness values supported that the classification of this strain as a novel species in the genus Micromonospora, for which the name Micromonospora spongicola sp. nov. (type strain S3-1(T) =BCC 45595(T)=NBRC 108779(T)) is proposed.