This study aims to determine the increase in students' interest and achievement of learning outcomes through the Discovery Learning model in science subjects on the material of the Human Respiratory System. The background of this study is the lack of student interest in participating in learning and the suboptimal achievement of student learning outcomes. This is indicated by the achievement of student learning outcomes that still do not meet the Minimum Completeness Criteria (KKM). This research uses the type of Classroom Action Research (PTK) which is carried out in 2 cycles. Each cycle is described in four stages, namely planning; implementation; observation; and ends with reflection. The research design used the Kemmis & Mc Taggart model. This research was conducted in the even semester of the 2022/2023 school year, namely in May 2023 with a research sample of 30 students. the data collection method used was observation to measure student interest in learning and evaluation tests used to measure student learning outcomes. This study used data analysis techniques in the form of quantitative and qualitative descriptive techniques. The results showed an increase in student interest in learning from 68.33% in cycle I to 84.99% in cycle II. The achievement of student learning outcomes measured through tests also increased, from 36.67% in cycle I to 56.67% in cycle II. Thus, the application of the Discovery Learning model learning model in the subject of Human Respiratory System can increase the interest and achievement of learning learning outcomes of students in class VIII A SMP Muhammadiyah Sewon.