Penelitian ini bertujuan untuk menghasilkan perangkat pembelajaran matematika berupa Rencana Pelaksanaan Pembelajaran (RPP), Petunjuk Kegiatan Siswa (PKS), dan Tes Ketercapaian Kompetensi (TKK) berbasis open-ended approach yang layak dalam mengembangkan keterampilan berpikir tingkat tinggi pada siswa SMA. Penelitian ini merupakan penelitian pengembangan yang terdiri atas 3 tahap utama, yaitu pendahuluan, desain produk, dan pengembangan dan evaluasi. Subjek uji coba penelitian yaitu 105 siswa, seorang guru SMAN 1 Barabai, seorang guru SMAN 2 Barabai, dan seorang guru SMAN 8 Barabai. Instrumen penelitian yang digunakan adalah lembar validasi, lembar penilaian guru, lembar penilaian siswa, lembar observasi keterlaksanaan kegiatan pembelajaran, dan TKK. Penelitian ini menghasilkan perangkat pembelajaran matematika berupa RPP dan PKS dengan kriteria valid, praktis, dan efektif dalam mengembangkan keterampilan berpikir tingkat tinggi pada siswa, serta TKK yang telah memenuhi kriteria valid, praktis, dan reliabel. Kata Kunci: pengembangan, perangkat pembelajaran, keterampilan berpikir tingkat tinggi   Math learning software development based open-ended approach to develop HOTS in high school students   Abstract This study aimed to produce a mathematics kitwhich were lesson plan, student activities manual (SAM), and the competency achievement tests (CAT) that was able to develop students higher order thinking skills in senior high school. This research was a development research which consists of 3 main stages, namely preliminary, product desain, development and evaluation. The tryout subjects of research were 105 students, one teacher of SMAN 1 Barabai, one teacher of SMAN 2 Barabai, and one teacher of SMAN 8 Barabai. The research instrument used was a validation sheet, teacher assessment sheet, student assessment sheets, feasibility observation sheets of learning activities, and CAT. This study resulted the mathematics learning kit in the form lesson plan and SAM meets the criteria of validity, practicality, and effectiveness which were able to develop higher order thinking skills, and CAT meets the criteria of validity, practically, and reliable. Keywords: development, learning kit, higher order thinking skills