The technical barriers to video production are decreasing and the popularity of video as an instructional medium in science is increasing. Although a large body of education research is available to inform the selection and design of instructional videos, this research is dispersed across journals, disciplinary traditions, and STEM fields, and the practical lessons are not readily accessible to readers. To guide the development and critique of science and mathematics instructional videos, our interdisciplinary team, with members from mathematics, physics, chemistry, and biology, has developed an instrument by synthesizing the relevant education literature and translating it into recommendations for practice. The user-friendly instrument is a 12-item checklist grouped into the categories of content and sequencing (concepts, logic, story, and language), cognitive supports (visualizations, signals, synchronization, segmentation, and streamlining) and affective considerations (relevance, rapport, and accessibility). The instrument provides a conceptual foundation and evaluation framework for designers of educational videos.