The abundance and species richness of moths were evaluated at 16 sites in southern South Korea to assess moth diversity and to identify indicator species for different forest types in this area. In total, 975 moth species were identified in the seven 6-mo collection periods (May–October) between 2001 and 2007. A matrix of 536 species and 36 sampling units was adopted for clustering sampling sites, and indicator species were determined after removing species with fewer than five individuals (370 species), and species that were found at fewer than three sites (36 species). Five different forest groups were identified based on clustering analysis: 1) seashore secondary forest, 2) evergreen deciduous forest, 3) inland young secondary forest, 4) inland mixed deciduous forest, and 5) inland high elevation conifer and deciduous forest. Patterns of moth abundance and species richness within four of the five groups were similar, but the abundance and species richness in the high elevation sites were significantly lower than in the other four groups. Sixty-three species were recognized in the five different forests based on indicator species analysis and the adoption of 63 indicator species in nonmetric multidimensional scaling ordination corroborated the grouping of sites into five groups. Many indicator species were woody plant feeders. In the current study, we determined the general pattern of moth diversity in different forest types in southern South Korea and identified indicator moth species that can be used to track future changes in forest structure as the forests age.