Abstrak.Penelitian ini bertujuan untuk menghasilkan modul menulis cerpen berbasis Project Based Learning (PjBL) yang valid, praktis, dan efektif untuk digunakan oleh siswa kelas X MA Ar-Risalah Padang. Subjek penelitian ini adalah siswa kelas X MA Ar-Risalah Padang yang berjumlah tiga puluh orang. Pemilihan subjek penelitian berdasarkan pertimbangan-pertimbangan tertentu. Penelitian ini merupakan penelitian pengembangan dengan menggunakan model pengembangan 4D. Pengembangan diawali dengan tahap pendefinisian, perancangan, dan diakhiri dengan pengembangan. Penelitian dimulai pada bulan Desember 2015 sampai dengan Maret 2015. Selama penelitian, peneliti berkolaborasi dengan guru bahasa Indonesia. Data penelitian yang berbentuk kuantitatif diperoleh dari penilaian validator ahli, guru dan siswa, dan hasil belajar siswa. Berdasarkan analisis data dan pembahasan dapat disimpulkan sebagai berikut. Pertama, validitas modul menulis cerpen berbasis PjBL yang dikembangkan tergolong sangat valid dengan presentase 95,83%. Kedua, praktikalitas yang dikembangkan tergolong sangat praktis dengan presentase 91,83% dan 81,43%. Ketiga, efektivitas modul menulis cerpen berbasis PjBL yang dikembangkan tergolong sangat efektif dengan persentase penilaian pada aktivitas siswa yakni 90,33%. Sebanyak 83,3% dari 30 siswa telah mendapatkan nilai menulis cerpen melebihi KKM. Jadi, modul yang telah dikembangkan dapat digunakan sebagai bahan ajar di dalam pembelajaran bahasa Indonesia khususnya untuk materi menulis cerpen.Kata Kunci: modul, project based learning, cerpenAbstract.This research is purposed to create a valid, practical, and effective modul of short story writing based on Project Based Learning (PjBL) for students of X class MA Ar-Risalah Padang. The subject of this research was students of X class MA Ar-Risalah Padang that amounted to 30 students. Research subject was selected with certain considerations. This research was development research by 4D development model. The development was began with definition and planning stages, and ended by development stage. This research was conducted from December 2014 to March 2015. During research, writer was collaborated with Indonesian language teacher. Research data was qualitative data which obtained from validation assessment of expert, teacher and student, and also student’s learning outcomes. Based on data analysis and discussion, it can be drawn some conclusions. First, validation of short story modul construction based on PjBL is valid with percentage of 95.83%. Second, practicality of short story modul that being developed is highly practical with percentage of 91.83% and 81.43%. Third, effectiveness of short story modul construction based on PjBL is very effective with assessment percentage in student activities is 90.33%. There is 83.3% of student have learning scores beyond KKM score. Therefore, modul that being developed in this research is applicable as learning material in Indonesian language learning especially for short story writing subject.Keywords: module, project based learning, short strory