Teachers' approaches and mindsets for assessment affect student learning, motivation, and social-emotional well-being. This systematic review examines how initial teacher education programs prepare teachers to enact one core purpose of classroom assessment--assessment for learning (AfL). AfL (also known as formative assessment) is a planned process of instructionally embedded assessment wherein students and teachers collaborate within goal-driven activity, monitor and communicate around evidence of learning, and reflect on evidence of learning to strategize actions to improve. We examined how teacher candidates learned to enact AfL within 70 studies published between 1998 and May 2022. Results illuminate how teacher candidates can learn to enact AfL through a combination of explicit instruction, modeling of AfL, and cyclical opportunities to enact AfL; get feedback; and attune instruction/assessment during their teacher preparation. However, we also uncovered contexts, structures, and practical considerations within teacher education that limit teacher candidates' learning and enactment of AfL.