The flipped classroom pedagogy has gained prominence in various educational contexts by reorganising the lectures of content knowledge via instructional videos, and squeezing in more time for class activities. Although there have been numerous studies of the design, implementation, and evaluation of the flipped approach, their outcomes varied in different disciplines. A pioneering scoping review was conducted to examine and illustrate existing research in K-12 science education. This study identified 358 peer-reviewed articles 15 of which were selected for analysis using a rigorously established five-stage scoping framework. The results indicated an overall positive impact from flipped classrooms, on motivation, engagement, and attitude, but there were mixed findings regarding academic performance. As in other flipped learning reviews, several student-related, faculty-related, and operation-related challenges were also identified in K-12 science education. To explore the current research gaps for flipping science classes, the identified studies were further analysed using a refined Spector's six pillars, and the synergetic incorporation of self-regulated and technology-enhanced predict-observe-explain (POE) strategies into flipped classrooms in K-12 science education was proposed.