This chapter seeks to describe an alternative licensure program, Aggie Prep, developed to address the needs of underrepresented students in the Southwest. The aim of the program was to prepare culturally and linguistically responsive first-year teachers seeking secondary alternative certification in science or mathematics. We discuss how this innovative alternative licensure program for secondary STEM teachers utilizes a competency-based curriculum with a practice-based approach to strategically identify opportunities to integrate science, mathematics, literacy, and language instruction for culturally and linguistically diverse youth. We specifically outline the use of ongoing professional development in the form of coursework, field coaching, mentoring and targeted professional development. The program assists beginning teachers to (1) make science, mathematics and language learning accessible; (2) elevate content rigor; (3) plan with print and non-print text in mind; and (4) build collaborative learning environments with attention to integrated content, language and literacy through a contextualized science, mathematics, and engineering approach. An integral part of this approach was the emphasis on the use of engaging inquiry-based activities. We share how we support our students’ ability to reflect on the nature of content, how adolescents learn, and implement instructional best practices of science and mathematics that accommodate the language and learning needs of students in their classrooms