In this analytical paper, we argue for the centrality of teachers in game-based learning (GBL) interventions. We examine the following research question, "What principles emerge from teacher education in game-based learning research conducted from 2007-2018?". In doing so, we examine evidence generated over 10+ years deductively and inductively using thematic analysis, to identify six principles that can guide research and practice in teacher education for GBL. These principles include: (a) Teachers play an active role in GBL environments; (b) Games are a form of curriculum; (c) GBL is a way of facilitating learning; (d) Games are not contextually or pedagogically neutral; (e) Teachers' knowledge of GBL evolves over time; and (f) Teachers' professional identities impact GBL practice. We conclude with pathways to engage the teacher education community in a critical assessment of how we can scaffold teachers to identify-study-incorporate games for learning.