'Best Evidence Science Teaching' (BEST) is a collection of open-access, research-evidence-informed resources for science teaching at 11-14. BEST includes progression toolkits comprising sequenced learning steps, diagnostic questions and response activities. Case studies illustrate how teachers are using BEST resources. Observations and interview data from 12 teachers suggest that BEST allowed these teachers to develop their practice in the following key areas identified by the Education Endowment Foundation (EEF) "Improving Secondary Science" guidance report: preconceptions, memory, metacognitive talk, feedback, practical work and language of science. Findings suggest that research-evidence summaries were being used by teachers to inform how they describe and explain scientific concepts, listen to student responses, sequence teaching and select models and analogies. As such, they provided access to no-cost, subject-specific professional development 'just in time' for teaching.