Opportunities for professional development involving direct instruction and practical experience related to quantitative research methods are limited for working teachers in Japan. The main goal of this presentation is to describe the goals, outcomes, and applications of a collaborative professional development project designed specifically for the needs and interests of language teachers looking to get started with quantitative research in the classroom. Twenty-eight language teachers based at 20 universities around Japan participated in the 2018 Quantitative Research Methods Training Project. In 2018, teachers conducted a small-scale study in their own classrooms that investigated student engagement in an extensive reading activity using Xreading. Throughout the planning, implementation, data analysis, and write-up stages, teachers received guidance from the project coordinator through an online project site and live online instruction. The presenter will introduce the project goals and methods and then describe outcomes in terms of participation evidence, teacher feedback, and tangible products including conference presentations and published. Finally, participants will receive guidance on how they can apply the approach of the project to collaborate with a group of peers to build knowledge and skills doing small-scale quantitative studies. This project is supported by a JSPS Grant-In-Aid.