Critical thinking skills (CTS) is an important goal in higher education. The purpose of this study is to determine the practicality and effectiveness of the Science Technoloy Learning Cycle (STLC) model to empower CTS in the course of science concept development (SCD). This study is a pretest-posttest control group design by 4 theme in SCD course. The number of samples in this study was seventy-three students who were divided into experimental and control classes. By sampling technique, sample were from a population of students who took the SCD course in the department of elementary teacher education at PGRI University of Semarang in the academic year of 2018/2019. The results showed that the STLC model was practical or workable as indicated by the lecturer and students' activities classified into both good and very good categories. The STLC model was significantly effective in empowering CTS. For further research, the STLC as an alternative learning model that to empower critical thinking skills at various education level, especially in preparing teacher candidates.