Oral health may affect the occurence of dental caries. Dental caries is a demineralization process in email, dentin, and cementum caused by metabolic activity of microorganisms. According to Bloom concept (1974), there were four main factors affecting oral health, as follows: environment, behaviour (knowledge and attitude), health facility, and heredity. This study was aimed to evaluate the correlation between knowledge, attitude, and behaviour of oral health and dental caries status among students of  SMPN 1 Selogiri (junior high school), Wonogiri. This was an observational and analytical study with a cross sectional design. There were 123 students as subjects in this study. Prior to participation, subjects were asked to fill in the questionairre and sign on the informed consent. Dental examination was carried  out by using oral sonde and oral glass. The Spearman test obtained a p-value of 0.001 for the correlation between knowledge, attitude, and behaviour of oral health and dental caries status. In conclusion, there was a significant relationship between knowledge, attitude, and behaviour of oral health and dental caries status among students of SMP 1 Selogiri, Wonogiri.Keywords: knowledge, attitude, behaviour, cariesAbstrak: Kesehatan atau kebersihan rongga mulut dapat memengaruhi terjadinya karies gigi. Karies adalah suatu proses demineralisasi pada email, dentin, dan sementum yang disebabkan oleh aktivitas metabolik suatu mikroorganisme. Terdapat empat faktor utama yang memengaruhi kesehatan gigi menurut konsep Bloom tahun 1974 yaitu: lingkungan, perilaku (pengetahuan dan sikap), pelayanan kesehatan, dan keturunan (hereditas). Penelitian ini bertujuan untuk mengetahui hubungan pengetahuan, sikap dan perilaku kesehatan gigi mulut terhadap status karies siswa SMPN 1 Selogiri Kabupaten Wonogiri. Jenis penelitian ialah analitik observasional dengan desain potong lintang. Sebanyak 123 siswa menjadi subjek penelitian. Sebelum berpartisipasi dalam penelitian, subjek diminta untuk mengisi kuesioner serta informed consent. Peneliti melakukan pemeriksaan karies gigi pada subjek dengan menggunakan sonde dan kaca mulut. Hasil uji Spearman mendapatkan nilai p=0,001 untuk hubungan antara pengetahuan, sikap, dan perilaku kesehatan gigi mulut terhadap status karies. Simpulan penelitian ini ialah terdapat hubungan bermakna antara pengetahuan, sikap, dan perilaku kesehatan gigi mulut terhadap status karies siswa SMP Negeri 1 Selogiri Kabupaten Wonogiri.Kata kunci: pengetahuan, sikap, perilaku, karies