<![CDATA[This experimental research aimed to find out the effectiveness of discovery learning model in terms of student's mathematical problem solving skill. The population of this research was all grade eight students of Junior High School state of 3 Natar in academic year of 2017/2018 which were distributed into ten classes. The samples of this research were students of VIII-D and VIII-E class which were chosen by purposive sampling. The design of this research was posttest only control group design. The research data were obtained by the test of mathematical problem solving skill. The data analysis of this research used Mann-Whitney U test. Based on the research, it was concluded that discovery learning model was not effective in terms of students mathematical problem solving skill.Penelitian ini bertujuan untuk mengetahui efektivitas model discovery learning ditinjau dari kemampuan pemecahan masalah matematis siswa. Populasi penelitian ini adalah seluruh siswa kelas VIII semester ganjil SMP Negeri 3 Natar tahun pelajaran 2017/2018 yang terdistribusi dalam sepuluh kelas. Sampel penelitian ini adalah siswa kelas VIII-D dan VIII-E yang dipilih dengan teknik purposive sampling. Desain yang digunakan adalah posttest only control group design. Data penelitian diperoleh melalui tes kemampuan pemecahan masalah matematis siswa. Analisis data penelitian ini menggunakan uji Mann-Whitney U. Berdasarkan hasil penelitian dan pembahasan disimpulkan bahwa model discovery learning tidak efektif ditinjau dari kemampuan pemecahan masalah matematis siswa.Kata kunci: discovery learning,efektivitas, pemecahan masalah matematis siswa]]>
