Equipping elementary (i.e., grades K-5) teachers with adequate content and pedagogical knowledge to promote effective reading instruction based on the science of reading is a crucial piece of the reading education puzzle. We reviewed 20 empirical studies to examine the impact of teacher preparation and training programs on elementary teachers' knowledge of the science of reading, focusing on the foundational pillars of reading instruction, namely, phonological and phonemic awareness, phonics, and morphological awareness, as well as student outcomes in reading. We also identified program characteristics that promoted positive growth in teacher knowledge. Generally, findings support the effectiveness of training and preparation programs in increasing elementary teachers' knowledge of foundational constructs. Training in which teachers have the opportunity to apply their learned knowledge and skills under expert guidance produced the largest growth in teacher knowledge. Implications of findings are discussed.A ll students have the right to learn to read and, thus, the right to have access to knowledgeable literacy educators (International Literacy Association [ILA], 2019; UNESCO, n.d.) who under stand the science of reading, or "the accumulated knowledge about reading, reading development, and best practices for reading instruction obtained by the use of the scientific method" (Petscher et al., 2020, p. S268). Theoretical propositions such as the componential model of reading (Aaron, Joshi, Gooden, & Bentum, 2008) and the lattice model of the development of reading comprehension (Connor, 2016) highlight the importance of classroom factors in reading development, such as teachers' ability to plan and manage instructional activity, and the qual ity of literacy instruction. However, effective literacy instruction is quite complex (Connor et al., 2009) and should consider students' home learning environment, previous background knowledge and experi ences, and effective instructional methods that will produce the highest results for each child (Connor, 2016). Thus, teachers must possess a depth of knowledge, including content and pedagogical knowledge, and understand how to be socially just and culturally responsive in their practice (Mosley Wetzel et al., 2020).In their recent article pertaining to teacher preparation, Hoffman, Hikida, and Sailors (2020) pointed out that over 600 empirical studies on literacy teacher preparation were published between 1999 and 2018. These studies examined teachers' knowledge and practice through a wide range of methodologies and lenses, which was necessary given the complexity of effective literacy instruction. Hoffman et al. also argued
