<![CDATA[Abstract. This study was motivated by students' low level of understanding regarding the importance of avoiding free association in Islamic Religious Education. The objectives of this study were to identify students' initial level of understanding, describe the implementation of the Mission-Based Learning with Role-Playing and Investigation method, and examine the effectiveness of the method in improving students' understanding of the importance of avoiding free association among tenth-grade students at SMAN 14 Bandung. This study employed a quantitative approach using a quasi-experimental method with a Nonequivalent Control Group Design. The research sample consisted of an experimental class and a control class. Data were collected using an objective multiple-choice test that had been validated and tested for reliability. The data were analyzed using the Wilcoxon Signed Rank Test and the Mann-Whitney U Test because they were not normally distributed. The results showed that the mean score of the experimental group increased from 70.70 on the pretest to 86.16 on the posttest. The Wilcoxon Signed Rank Test indicated a significant improvement in the experimental group, while the Mann-Whitney U Test revealed a significant difference between the experimental and control groups after the treatment (p < 0.05). In addition, Cohen's d value of 0.636 indicated a medium effect size. Therefore, the Mission-Based Learning with Role-Playing and Investigation method was effective in improving students' understanding of the importance of avoiding free association in Islamic Religious Education. Keywords: Mission-Based Learning, Role-Playing, Investigation, Islamic Religious Education, Understanding. Abstrak. Penelitian ini dilatarbelakangi oleh rendahnya pemahaman peserta didik mengenai pentingnya menjauhi pergaulan bebas pada mata pelajaran Pendidikan Agama Islam (PAI). Penelitian ini bertujuan untuk mendeskripsikan kondisi awal pemahaman peserta didik, mendeskripsikan implementasi metode Mission-Based Learning with Role-Playing and Investigation, serta mengetahui efektivitas metode tersebut dalam meningkatkan pemahaman peserta didik kelas X SMAN 14 Bandung. Penelitian menggunakan pendekatan kuantitatif dengan metode quasi experiment melalui desain Nonequivalent Control Group Design. Sampel penelitian terdiri atas kelas eksperimen (43 siswa) dan kelas kontrol (42 siswa) yang ditentukan melalui purposive sampling. Pengumpulan data menggunakan tes objektif pilihan ganda yang telah diuji validitas dan reliabilitasnya. Analisis data dilakukan menggunakan uji Wilcoxon Signed-Rank Test dan Mann-Whitney U Test karena data penelitian tidak berdistribusi normal. Hasil penelitian menunjukkan bahwa rata-rata nilai kelompok eksperimen meningkat dari 70,70 pada saat pretest menjadi 86,16 pada saat posttest. Hasil uji Wilcoxon menunjukkan adanya peningkatan yang signifikan pada kelompok eksperimen, sedangkan hasil uji Mann-Whitney menunjukkan adanya perbedaan yang signifikan antara kelompok eksperimen dan kelompok kontrol setelah perlakuan diberikan (p < 0,05), dengan nilai Cohen's d sebesar 0,636 yang menunjukkan effect size kategori sedang. Dengan demikian, metode Mission-Based Learning with Role-Playing and Investigation efektif dalam meningkatkan pemahaman peserta didik mengenai pentingnya menjauhi pergaulan bebas pada mata pelajaran Pendidikan Agama Islam. Kata Kunci: Mission-Based Learning, Role-Playing, Investigation, Pendidikan Agama Islam, Pemahaman, Pergaulan Bebas.]]>
