Abstrak Penelitian dilakukan karena fakta bahwa terdapat siswa yang belum mampu memecahkan masalah pada materi himpunan. Penelitian kualitatif deskriptif ini bertujuan mendeskripsikan profil pemecahan masalah matematika siswa SMP terhadap materi himpunan ditinjau dari self efficacy. Subjek penelitian yaitu 3 siswa kelas VIII salah satu SMP Negeri di Salatiga. Instrumen utama adalah peneliti sendiri, didukung pedoman wawancara dan tes pemetaan pemecahan masalah. Hasil penelitian menunjukkan subjek berkemampuan tinggi dan sedang mampu merencanakan strategi penyelesaian soal dengan baik yang mempermudahnya menyelesaikan soal menentukan komplemen gabungan dan irisan dua himpunan, sedangkan subjek berkemampuan rendah belum mampu; subjek berkemampuan tinggi, sedang maupun rendah memiliki rasa optimis dan keyakinan pada diri yang tinggi; subjek berkemampuan tinggi, sedang dan rendah konsisten, ulet dan tekun dalam menyelesaikan soal; subjek berkemampuan tinggi dan sedang mampu menjadikan kesalahan sebelumnya sebagai pedoman untuk mencapai keberhasilan dalam penyelesaian soal, sedangkan subjek berkemampuan rendah kurang mampu. Hasil ini memberikan gambaran bahwa subjek ketiga tidak memiliki self efficacy yang berbeda secara signifikan meskipun kemampuan pemecahan masalah berbeda-beda. Profile of Solving Mathematical Problems on Set Materials in terms of Self Efficacy AbstractThis research was conducted based on the fact that there are still students who have not been able to solve problems on the set material. This descriptive qualitative research aims to describe the profile of solving mathematical problems about sets by junior high school students in terms of self-efficacy. The research subjects were 3 students of class VIII of one of the public junior high schools in Salatiga. The main instrument is the researcher herself who is supported by interview guides, documents, and problem-solving mapping tests of the set. The results showed that high and low-ability subjects were able to plan the problem-solving strategy well which made it easier for them to determine the combined and sliced complement of two sets. Subjects with high, medium and low abilities have a sense of optimism and high self-confidence, are consistent, resilient, and diligent in solving set problems. High and medium-ability subjects can make previous mistakes as a guideline for achieving success in problem-solving, while low-ability subjects are less capable. These results illustrate that the third subject does not have different self-efficacy even though their problem-solving abilities differ.