This quasi-experimental study investigated the effect of research-inquiry based teaching strategies on students' academic achievements (AA), attitudes, and scientific process skills (SPS). The study sample comprised 50 students studying in Grade 7 in a secondary school affiliated to the Ministry of Education (MoE) in Bartin. In this study, experiment and control groups were selected to determine the effect of research-inquiry based teaching strategies. A draft teaching program for the "Reflection and Light Absorption in Mirrors" topic was conducted for three weeks with the experimental group in accordance with the research-inquiry based teaching philosophy and in compliance with the achievements included in the MoE curriculum. In the control group, the regular Classroom Science Course Curriculum was followed. SPS Test, AA Test, and Attitude Scale were employed for the pre and posttests of the experimental and control groups. The test results were analyzed using quantitative analysis methods. The use of research-inquiry based strategies in science courses in research was thus found to have a positive impact on students' AA, attitudes, and SPS.