ABSTRAKPenelitian bertujuan untuk 1).Mengembangkan Model Discovery Learning yangdiintegrasikan dengan Group Investigation pada materi protista untuk meningkatkan hasilbelajar siswa kelas X SMA Negeri Karangpandan, 2). Menguji kelayakan Model DiscoveryLearning yang diintegrasikan dengan Group Investigation pada materi protista untukmeningkatkan hasil belajar siswa kelas X SMA Negeri Karangpandan, 3). Menguji keefektifanproduk Model Discovery Learning yang diintegrasikan dengan Group Investigation disertaimodul dan media untuk meningkatkan hasil belajar pada materi protisa kelas X SMA NegeriKarangpandan.Penelitian menggunakan metode Research And Development (R&D) mengacu padamodel Gall, Borg & Gall (2003) yang dimodifikasi menjadi 9 tahap yaitu 1). Penelitian danpengumpulan informasi, 2). Perencanaan, 3). Pengembangan Produk Awal, 4). Validasi produk5). Revisi Produk Awal, 6). Uji Coba Lapangan Skala Terbatas, 7). Revisi produk akhir, 8). UjiLapangan Operasional, 9). Revisi Produk Akhir. Kelayakan model divalidasi oleh ahli modeldan perangkat pembelajaran, ahli materi, dan guru praktisi. Subjek uji coba pada penelitianadalah semua siswa kelas X Mia SMA Negeri Karangpandan tahun pelajaran 2014/2015. KelasX Mia 1 adalah kelas model, X Mia 2 adalah kelas agregasi, dan X Mia 6 adalah kelas existinglearning. Data dikumpulkan dengan metode tes, angket, dan observasi, analisis dengan metodedeskriptif kualitatif dan hasil belajar kognitif dengan N-gain ternormalisasi untuk mengetahuikeefektifan model, Paired - Sample T test untuk mengetahui sebelum dan setelah penggunaanmodel, serta Independent t-test untuk mengetahui perbedaan hasil belajar kelas model, danagregasi. Data nilai pengetahuan kelas model, agregasi, dan existing learning diuji Anova .Pengembangan model DL yang diintegrasikan dengan GI pada materi Protistadilaksanakan dengan memperhatikan komponen model pembelajaran. Pengembangan modeldikembangkan untuk memberi kesiapan membangun pengetahuan kelompok yang lebih dalampembelajaran. Produk model dilengkapi perangkat pembelajaran meliputi Silabus, RPP, LKS,Instrumen evaluasi, dan Video pembelajaran. Hasil validasi materi terhadap modelpembelajaran sebesar 3,52 (sangat baik), hasil validasi ahli model dan perangkat sebesar 3,44(baik), dan hasil validasi praktisi sebesar 3,65 (sangat baik). Hasil uji coba skala kecil sebesar83,47 dengan kategori baik. Hasil N-gain ternomalisasi pada hasil belajar pengetahuan kelasmodel 0,58, agregasi 0,61,dan existing learning 0,39. Hasil belajar sebelum dan setelahpenggunaan model menunjukkan (sig.0,000<0,05). Berdasarkan hasil analisis menunjukkan 1).Pengembangan model dilaksanakan dengan memperhatikan karakteristik model; 2). Hasilpengembangan model berdasarkan penilaian hasil validasi ahli memperoleh kategori baik,praktisi, dan siswa kategori sangat baik serta layak digunakan di SMA Negeri Karangpandan;3). Pencapaian hasil belajar siswa setelah proses pembelajaran Model GDL menunjukkanpeningkatan baik dikelas model, kelas agregasi, dan kelas existing learning. Penerapan modelGDL disertai modul dan media mengalami peningkatan keefektifan hasil belajar pengetahuandan sikap, namun hasil belajar ketrampilan sama. Sedangkan pada kelas existing learning terjadipeningkatan keefektifan pada hasil belajar pengetahuan, pada hasil belajar sikap danketrampilan tidak nampak.Kata kunci : Discovery Learning, Group Investigation, Model GDL, Agregasi, Existinglearning, Hasil BelajarABSTRACTThe objectives of research are 1) to develop the Discovery Learning (DL) modelintegrated with Group Investigation (GI) on the topic of discussion of Protist to improve thelearning result of the students in Grade X of State Senior Secondary School of Karangpandan;2) to investigate the feasibility of the DL model integrated with GI on the topic of discussion ofProtist to improve the learning result of the students in Grade X of State Senior SecondarySchool of Karangpandan; and 3) to investigate the effectiveness of product of the DL modelintegrated with GI on the topic of discussion of Protist to improve the learning result of thestudents in Grade X of State Senior Secondary School of Karangpandan.The research employed the Research and Development method, which referred to themodel claim by Gall, Borg & Gall (2003), and which was modified into nine phases. Thefeasibility of the developed model was validated by experts of learning models and learninginstruments, experts of learning materials, Biology teachers (practitioners). The population ofresearch was all of the students in Grade X MIA of State Senior Secondary School in AcademicYear 2014/2015; Grade X MIA 1 became the model class, whereas Grade MIA 2 wasaggregation class. The data of research were gathered through test, questionnaire, andobservation. They were analyzed by using the descriptive qualitative method. Meanwhile, theresult of cognitive learning was analyzed by using normalized N-gain to investigate theeffectiveness of the developed learning model, Paired- Sample T test to investigate the learningresults prior to and following the model use, and Independent t test to investigate the differencein the learning result of model class and that of aggregation class.The result of validation on the DL model integrated with GI is 3.52 (very good). Theresult of validation by experts of learning models on the DL model integrated with GI is 3.44(good), whereas that of validation by practitioners is 3.65 (very good). The result of small-scaleexperiment is 83.47 with good category. The results of research are as follows 1) Thedevelopment of DL model integrated with GI is implemented by considering the learning modelcharacteristics, namely: syntax, social system, support system, reaction principle, instructionaleffect, and nurturant effect; 2) The result of the development of DL model integrated with GIshows that is it is feasible to be applied on the topic of discussion of Prostist. It belongs to goodcategory and is feasible to be used in State Senior Secondary School of Karangpandan; and 3)and The DL model integrated with GI is able to improve students’ learning result. Thus, theresults of research show that there is a significant difference in the results of knowledge andattitude learning between the model class and aggregation class, there is not any difference inthe results of skill learning.Keywords: Discovery learning, Group Investigation, and Learning Result.