Dental caries is one of the most prevalent infectious diseases in Indonesia. More than half of all cases are left untreated. This may be due to inequity in the use of dental care that is caused by economic and geographic barriers. Therefore, the objective of this study was to provide evidence of socioeconomic-related inequality and horizontal inequity in dental care utilization among Indonesian adults who reported having had dental problems and to describe the sources of any identified inequality. We used secondary cross-sectional data from the Indonesian National Socio-Economic Survey 2004 and from the Indonesian Medical Council. Respondents included individuals at least 15 years old who reported having had dental care needs within a one-month recall period (N = 20,718). A concentration curve and a concentration index were employed to describe the extent of inequality. A horizontal inequity index was applied to identify inequity. A decomposition method was used to describe the sources of inequality. The concentration curve indicated a slightly pro-rich inequality in dental care utilization. The concentration index showed a significant concentration of dental care utilization among groups with higher socioeconomic status (SES). The horizontal inequity index illustrated higher unmet dental care needs among lower SES groups. Decomposition revealed that higher SES, urban Java Island residency, and insurance coverage were positively associated with the likelihood of dental care utilization. This study concludes that the expansion of health insurance, especially targeted at low SES groups, and a regionally equitable distribution of dentists may reduce economic and geographic barriers to dental care in the future.