Latar Belakang: Otonomi seksual perempuan merupakan determinan penting kesehatan reproduksi, termasuk risiko infeksi menular seksual (IMS), namun studinya masih terbatas di Indonesia. Penelitian ini bertujuan menganalisis distribusi dan determinan otonomi seksual perempuan berpasangan serta hubungannya dengan self-reported IMS. Metode: Studi ini menggunakan desain explanatory sequential mixed-methods. Tahap kuantitatif menggunakan data SDKI 2017 (cross-sectional) melibatkan perempuan berpasangan usia 15–49 tahun. Analisis data menggunakan Principal Component Analysis (PCA), Chi-Square, regresi logistik, dan regresi multilevel pada 19 variabel (faktor individu, relasional, masyarakat). Tahap kualitatif berupa wawancara mendalam lintas pemangku kepentingan untuk mengeksplorasi temuan kuantitatif. Hasil: Mayoritas responden memiliki otonomi seksual tinggi (54,2%), dengan tingkat pendidikan sebagai determinan paling dominan (OR=3,63). Analisis multilevel menunjukkan perbedaan antarprovinsi (faktor makro) berkontribusi sebesar 33,4% terhadap variasi otonomi seksual. Otonomi seksual rendah berhubungan dengan penurunan pelaporan gejala IMS sebesar 0,60 kali setelah dikontrol variabel sikap kekerasan fisik, pengetahuan HIV/AIDS dan IMS,  otonomi pengambilan keputusan, pekerjaan, dan usia responden.  Hal ini berkaitan dengan health-seeking behavior di tengah stigma masyarakat, di mana sikap terhadap kekerasan fisik menjadi prediktor dominan kejadian IMS (AOR=2,14). Kesimpulan: Otonomi seksual perempuan di Indonesia dipengaruhi secara kuat oleh struktur lingkungan dan agama. Intervensi kesehatan reproduksi harus diintegrasikan dengan penguatan kesetaraan gender di ranah domestik untuk meningkatkan otonomi seksual dan menekan transmisi IMS.

Background: Women's sexual autonomy is a critical determinant of reproductive health, including the risk of Sexually Transmitted Infections (STIs); however, studies on this topic remain limited in Indonesia. This study aims to analyze the distribution and determinants of sexual autonomy among partnered women and its association with STIs. Methods: This study employed an explanatory sequential mixed-methods design. The quantitative phase utilized cross-sectional data from the 2017 Indonesia Demographic and Health Survey (IDHS), involving partnered women aged 15–49 years. Data were analyzed using Principal Component Analysis (PCA), Chi-Square, logistic regression, and multilevel regression across 19 variables encompassing individual, relational, and community factors. The qualitative phase consisted of in-depth interviews across multiple stakeholders to explain the quantitative findings. Results: The majority of respondents demonstrated high sexual autonomy (54.2%), with educational attainment emerging as the most dominant determinant (OR=3.63). Multilevel analysis revealed that inter-provincial variations (macro factors) contributed 33.4% to the variance in sexual autonomy. Low sexual autonomy was associated with a 0.60-fold decrease in reporting STI symptoms after adjusting for variables such as attitudes toward physical violence, knowledge of HIV/AIDS and STIs, decision-making autonomy, employment, and respondents' age. This phenomenon is closely linked to health-seeking behavior amidst social stigma, wherein attitudes toward physical violence served as the dominant predictor for STI occurrence (AOR=2.14). Conclusion: Women's sexual autonomy in Indonesia is strongly influenced by environmental structures and religion. Reproductive health interventions must be integrated with the strengthening of gender equality within the domestic sphere to enhance sexual autonomy and mitigate STI transmission.