The aim of study to investigate the effects of block-based game development activities carried out on the goal-based scenario approach on the geometry achievement and computational thinking skills of seventh-grade students and to reveal their opinions regarding the process. The study used a one-group pretest-posttest experimental model an experimental research design. Overall, 43 seventh-grade students from a district of the province of Van, Turkey, during the 2021-2022 academic year constituted the participants of the study. The participants were determined using the criterion sampling technique a purposeful sampling technique. Within the scope of the study, a goal-based scenario about the topic of polygons was presented to the students, and implementations were carried out. The Computational Thinking Skills Scale, polygons achievement test and a structured interview form were used to collect data. The quantitative data obtained were analyzed using t-test, and the qualitative data were analyzed using content analysis. The results revealed that the block-based game development activities carried.