The purpose of this study was to explore science teacher perceptions regarding the most effective professional learning opportunities. This descriptive study surveyed 118 candidates for National Board certification in Adolescent and Young Adult Science from 42 states about their professional learning experiences. Candidates' self‐reports reveal that developing science curriculum, reading scientific literature, and pursuing National Board certification are the three most productive approaches to professional development while education courses and in‐service workshops were identified as least effective.