The purpose of this study is to determine the opinions and self-efficacy beliefs of middle school students towards mathematical connections before and after the process in a learning environment prepared in the context of connections with different disciplines and including modeling tasks. An embedded experimental mixed method design was used in the research. The study was conducted with a sum of sixty-one students in the seventh-grade experimental and control groups for fifteen weeks, including the pre-test, post-test, and application process. As a data collection tool, mathematical modelling tasks, mathematical connection self-efficacy scale, and pre-post opinion forms for mathematical connection were applied. It was observed that there is no statistically meaningful difference between the pre-test and post-test scores of the groups in terms of mathematical connection self-efficacy. However, after the process, it was specified that connecting mathematics with other disciplines assisted the development of students' opinions on mathematics and different courses.