Abstrakujuan penelitian ini adalah mendeskripsikan proses pembelajaran, mengetahui peningkatan prestasi siswa, dan mendeskripsikan perubahan perilaku siswa dalam pembelajaran PKn melalui tugas proyek berbantuan website. Penelitian ini dilaksanakan dalam 2 Siklus dengan subjek siswa kelas IV SD Negeri Gegunung Kulon, Kabupaten Rembang, semester 2 tahun pelajaran 2014/2015. Data penelitian dianalisis dengan metode deskriptif komparatif, membandingkan proses dan hasil belajar antara praSiklus, Siklus I dan Siklus II. Hasil penelitian yang dilaksanakan 2 Siklus menunjukkan peningkatan aktivitas siswa sampai 86 persen baik. Hasil belajar siswa juga meningkat ditandai Siklus I nilai rata-rata kelas 67,86 dan ketuntasan mencapai 57 persen. Siklus II nilai rata-rata kelas 78,57 dan ketuntasan 86 persen. Kesimpulan penelitian ini adalah aktivitas dan hasil belajar siswa meningkat dalam mengikuti pembelajaran serta ada perubahan perilaku siswa untuk mengikuti pembelajaran PKn melalui tugas proyek berbantuan website yang semula pasif menjadi lebih aktif. Semua siswa berminat dalam melaksakanan tugas dan memperoleh pengalaman yang menyenangkan dalam menjelajah website atau internet. AbstractThe objective of this research was to describe learning process, to know how students’ learning achievement improve, and to describe the change of student behavior on civics learning through website-assisted project task. The research was done through two cycles, with grade IV students in SD Negeri Gegunung Kulon throughout the second semester of school year 2014/2015 as the subject. Research data analysis was done using descriptive comparative method, comparing the learning process and result between pra-cycle, first cycle and second cycle. The result showed positive increase of students’ activities as much as 86 percent. The improvement of students’ learning achievement in cycle I could be seen by the class average grade of 67,86 and mastery learning of 57 percent, while in cycle II the class average grade was 78,57 and mastery learning of 86 percent. The conclusion was that students’ learning activities and achievement improved and there was also a changing in students’ behavior in learning civics through website-assisted project task, from passive learning to active learning. Every student showed interest in doing the project and gaining enjoyable experience browsing the internet.