We conducted a scoping review on game-based learning (GBL) for mathematics teacher education. In recent decades, GBL has been largely applied to K-12 education contexts. GBL has aimed to promote students' deeper understanding of mathematics knowledge via game-based activities. With the evolving needs of GBL in mathematics education, recent research has increasingly raised the importance of mathematics teacher development specialised in GBL implementation. However, there is a lack of literature synthesis identifying how GBL has been taught and developed for mathematics teachers. Using both bibliometric and qualitative thematic analysis, we identified key characteristics of GBL design and implementations for various mathematics learning contexts in teacher education. Based on the study findings, we identified key trends and issues of GBL in mathematics teacher education. Also, we suggest theoretical and design implications of GBL for mathematics teacher education.