This study investigated developmental trajectories of novice elementary "teachers' efficacy beliefs" (i.e., personal teaching efficacy and outcome expectancy) and their "mathematical knowledge for teaching" (MKT). Overall, study findings indicated growth in participants' personal efficacy beliefs and in various assessments for dimensions of MKT. Additional relationships between participants' MKT trajectories and their mathematics efficacy beliefs trajectories were found. Findings from our study can help teacher educators, researchers, and school leaders in better understanding how novice teachers develop their MKT and their teaching efficacy beliefs during the teacher education program and in their first years of teaching.