Evidence-Based Reasoning (EBR) is a framework of inquiry-based teaching for developing scientific reasoning. This research aims to analyze the effectiveness of EBR in inquiry-based Physics teaching to improve students' scientific reasoning. Applying Slovin formula for sample determination, the research involved 139 upper-secondary school students with similar prior knowledge. This research used one group pre-test post-test design with replication. The effectiveness of teaching on improving

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... tific reasoning was analyzed by using Paired Sample T-test. ANOVA was used to analyze the consistency of the teaching effectiveness across in test group. The findings indicated that EBR effectively improved students' scientific reasoning in inquiry-based Physics teaching based on two main grounds. On the first, the significance was ensured by N-gain category of scientific reasoning component, which proved (a) control of variables reaching high category, (b) proportional thinking at moderate category; c) probabilistic thinking reaching moderate category, (d) hypothetical-deductive reasoning attaining low category; and (e) correlational thinking achieving low category. In addition, the level of scientific reasoning has attained the experience characterized by slightly imperfect answers. Students voiced positive response to EBR, which stated that it helped them engage in scientific reasoning in Physics learning. They also voiced the general opinion on EBR and inquiry-based learning in general. Keywords: evidence-based reasoning, inquiry teaching, physics teaching, scientific reasoning.