Penelitian ini bertujuan untuk mendeskripsikan dan membandingkan keefektifan pendekatan problem posing dan pendekatan konvensional ditinjau dari prestasi belajar, kemampuan koneksi matematis, dan disposisi matematis. Jenis penelitian ini adalah eksperimen semu. Populasi mencakup seluruh siswa kelas VIII SMP Negeri 1 Tempel Sleman yang terdiri atas 6 kelas. Kelas VIII A dan VIII D terpilih secara acak sebagai sampel. Kelas VIII D sebagai kelas eksperimen diberikan pembelajaran dengan pendekatan problem posing. Kelas VIII A sebagai kelas kontrol diberikan pembelajaran konvensional. Teknik pengumpulan data menggunakan tes dan nontes, sedangkan instrumen yang digunakan meliputi soal tes prestasi belajar, soal tes kemampuan koneksi matematis, dan angket disposisi matematis siswa. Teknik analisis data menggunakan uji MANOVA,  uji t satu sampel, dan uji t dua sampel independen. Hasil penelitian pada taraf signifikan 5% menunjukkan bahwa pendekatan problem posing efektif ditinjau dari prestasi belajar dan kemampuan koneksi matematis. Pembelajaran konvensional tidak efektif ditinjau dari prestasi belajar, kemampuan koneksi matematis, dan disposisi matematis. Pendekatan pembelajaran problem posing lebih unggul dibandingkan dengan pembelajaran konvensional ditinjau dari prestasi belajar dan kemampuan koneksi matematis.Kata kunci: pendekatan pembelajaran problem posing, prestasi belajar, kemampuan koneksi matematis, disposisi matematis. The Effectiveness of Problem Posing Approach in Terms of Achievement, Mathematical Connection Ability and Mathematical Disposition in Mathematics AbstractThe aims of this study were to describe the effectiveness of problem posing approach, the conventional approach, and the comparison of the effectiveness between problem posing approach and conventional approach in terms of  achievement, mathematical connection ability, and mathematical disposition. The research design used quasi-experimental.. The population consisted of all 8th grade in State Junior High School 1 Tempel Sleman consisting of six classes. There were two classes involved. Class VIII D as the experiment class was taught using problem posing approach, while class VIII A as the control class was taught using conventional learning. The data collecting techniques were a test and non-test whereas the instruments were used to collect the data consisted of a mathematical achievement test, a mathematical connection test and a mathematical disposition questionnaire. The data were analyzed using MANOVA test, one sample t test, and two samples independent t test. The result of the study by using significance level 5%, showed that the problem posing approach was only effective in terms of achievement and mathematical connection ability. Conventional approach was not effective in terms of student’s achievement, mathematical connection ability and mathematical disposition. Problem-posing approach  was more excellent compared to conventional learning in terms of student’s achievement ability and  mathematical connection ability.Keywords: problem posing approach, learning achievement, mathematical connection ability and mathematical disposition