The goal of this research was to test the effectiveness of a new science curriculum focused on increasing awareness and knowledge of microplastic pollution in middle school students. The curriculum utilized three teaching methods including lectures, object-mediated learning, and peer collaboration to enhance student engagement and learning. The 84 participants were 8th-grade students between the ages of 13 and 15. Lesson effectiveness was evaluated using pre- and post-assessment questionnaires to compare student knowledge and awareness of microplastic pollution before and after the lesson. In the pretest, 90% of student definitions of microplastics were descriptive referring to microplastics as "small" or "tiny" pieces of plastic. The remaining 10% stated they had no previous knowledge of microplastics. In the post-assessment, 100% of students provided a definition, with 23% of them identifying microplastics with the scientifically defined size (< 5 mm). The number of student definitions that also contained one or more elements of microplastic pollution, i.e. impacts and/or sources of origin increased between the pre- and post-assessment. Of the student posters, 81% demonstrated plastic pollution in an aquatic environment. A total of 9 posters (n = 16) contained explicit text and/or images on microplastic pollution with 5 highlighting harmful ingestion of microplastics by marine life. Student ratings of their enjoyment and learning experience from taking part in the lesson were high, with most students rating 4 or 5 on a 1 (no enjoyment or knowledge learned) to 5 (enjoyable/learned something new) scale. The results indicate that this curriculum was successful in increasing student knowledge and awareness of microplastic pollution.