Abstrak Penelitian bertujuan untuk mengembangkan instrumen Microteaching berkesesuaian dengan keterampilan abad ke-21 yang valid dan reliabel sehingga layak digunakan. Bentuk penelitian yang digunakan adalah Research and Development (R&D) dengan mengikuti alur pengembangan ADDIE (Analyze, Design, Develop, Implement, and Evaluate). Subjek penelitian yaitu 30 dosen dan 70 mahasiswa. Validitas instrumen menggunakan Content Validity Index dan Face Validity yang menunjukkan bahwa instrumen dinyatakan valid. Reliabilitas instrumen menggunakan koefisien interkelas korelasi pada merancang dan melaksanakan pembelajaran dan diperoleh nilai koefisien interkelas korelasi dengan kategori sangat reliabel. Berdasarkan hasil penelitian disimpulkan bahwa instrumen yang dikembangkan valid dan layak digunakan untuk mengukur keterampilan peserta Microteaching dalam merancang dan melaksanakan proses pembelajaran abad ke-21. AbstractThe aim of this research was to develop Microteaching assessment instrument that are compatible with the 21st-century skill that is valid and reliable so that appropriate to use. The design of this research was Research and Development (R&D) which refers to ADDIE (Analyze, Design, Develop, Implement, and Evaluate). The research subjects were 30 lecturers and 70 students. The validity of the instrument using the Content Validity Index and Face Validity showed that the instrument was valid. Instrument reliability was using the intraclass correlation coefficient in designing and implementing the learning process obtained result as very reliable. It can be concluded that the developed instrument was valid to be used in assessing participant’s Microteaching skills in designing and implementing the 21st-century learning process.