Background: Indonesia has the largest population of all countries in southeast Asia. However, little information is available on the oral health status of Indonesian children. The aims of this study were to assess dental caries and erosive tooth wear in 12-year-old children in Jakarta, Indonesia and to investigate the associated risk factors. Methods: Samples were selected using cluster sampling. Parents were asked to complete a self-administered questionnaire regarding their oral health knowledge, demographic information, their child’s dietary habits, and oral health-related behaviors. Experience of caries and erosive tooth wear were recorded using the Decayed, Missing (due to caries), and Filled Teeth (DMFT) index and the Basic Erosive Wear Examination (BEWE) index, respectively. Results: Of 779 children invited, 696 participated in the survey. Of these, 61% had experienced caries, and the mean DMFT score was 1.58. Almost all decay was untreated. Children who were female, who had a high frequency of soft drink intake, and whose father’s educational level was low were more likely to have dental caries. Most children had at least one lesion of erosive tooth wear. Children whose mother’s educational level was low were more likely to have erosive tooth wear. Conclusions: The prevalence of dental caries and erosive tooth wear was high in 12-year-old children in Jakarta. Their dietary habits and parental level of education were associated with the presence of these dental conditions.